Sugarcane crop-ebook

Ebook on Sugar Cane

2. 1
Foreword

Numerous books and documents have been written and published about the
sugarcane crop, documenting cultivation practices associated with its culture. A vast
majority of these describing agronomic practices are adequate in written text, but are
inadequate in directing the reader about field practical skills in growing sugarcane.

To be viable and competitive, sugarcane growers face many challenges. These require
significant economic and social restructuring and the adoption of new, complex and
high-risk technologies. The main prerequisites for these decisions are the availability of
high quality, timely and relevant information.

More than ever, sugarcane farmers, cane department officials of sugar factories,
technicians, extension workers, students, consultants, bank officials, teachers and
research scientists need to understand the whys and how's of modern sugarcane
production with drip irrigation.

But recommendations given to farmers often do not answer questions such as growing
method, drip system guidelines, how to increase the efficiency of water use and
applied fertilizer through fertigation, how to lessen the chance of lodging etc. This is
why there is a wide gap between the potential and actual productivities in most
sugarcane growing regions of the world.

Producing this information was a challenge for Netafim ACS, Israel. The existing
information system on drip irrigated sugarcane crop lacks adaptability to local
conditions, completeness, quality, easy access and regular updating. Over the last 45
years Netafim has developed many crop growing manuals to address these
deficiencies. This has culminated in this new series of growing guide on web pages.

3. 2

Introduction

Sugarcane, Saccharum officinarum L., an old energy source for human beings and,
more recently, a replacement of fossil fuel for motor vehicles, was first grown in South
East Asia and Western India. Around 327 B.C. it was an important crop in the Indian
sub-continent. It was introduced to Egypt around 647 A.D. and, about one century
later, to Spain (755 A.D.).


Global Distribution of Sugarcane (Click to Enlarge)

Since then, the cultivation of sugarcane was extended to nearly all tropical and sub-
tropical regions. Portuguese and Spaniards took it to the New World early in the XVI
century. It was introduced to the United States of America (Louisiana) around 1741.

Botanically, sugarcane belongs to the Andropogonae tribe of the family Gramineae,
order Glumiflorae, class Monocotyledoneae, subdivision Angiospermae, division
Embryophita siphonogama. The subtribe is Sacharae and the genus, of course,
Saccharum, derived from the Sanskrit "sarkara = white sugar", a reminder that the
plant reached the Mediterranean region from India.

Sugarcane growing countries of the world are lying between the latitude 36.7° north
and 31.0° south of the equator extending from tropical to subtropical zones. This
map depicts the distribution of sugarcane in the world.

Worldwide sugarcane occupies an area of 20.42 million ha with a total production of
1333 million metric tons (FAO, 2003). Sugarcane area and productivity differ widely

4. 3
from country to country (Table 1). Brazil has the highest area (5.343 million ha), while
Australia has the highest productivity (85.1 tons/ha). Out of 121 sugarcane producing
countries, fifteen countries (Brazil, India, China, Thailand, Pakistan, Mexico, Cuba,
Columbia, Australia, USA, Philippines, South Africa, Argentina, Myanmar, Bangladesh)
86% of area and 87.1% of production (Table 1). Out of the total white crystal sugar
production, approximately 70% comes from sugarcane and 30% from sugar beet.

Sugarcane area and productivity differ widely from country to country (Table 1). Brazil
has the highest area (5.343 million ha), while Australia has the highest productivity
(85.1 tons/ha). Out of 90 sugarcane producing countries, fifteen countries (Brazil,
India, China, Thailand, Pakistan, Mexico, Cuba, Columbia, Australia, USA, Philippines,
South Africa, Argentina, Myanmar, Bangladesh) 86% of area and 87.1% of production
(Table 1).

Table 1. Sugarcane In The world: Area, Production And Productivity
Country
Area
(million ha)
Production (million tons)
Productivity
(Tons/ha)
Brazil 5.343 386.2 72.3
India 4.608 289.6 62.8
China 1.328 92.3 65.5
Thailand 0.970 64.4 66.4
Pakistan 1.086 52.0 47.9
Mexico 0.639 45.1 70.6
Colombia 0.435 36.6 84.1
Australia 0.423 36.0 85.1
USA 0.404 31.3 77.5
Philippines 0.385 25.8 67.1
Indonesia 0.350 25.6 73.1
Cuba 0.654 22.9 35.0
South Africa 0.325 20.6 63.4
Argentina 0.295 19.2 65.2
Myanmar 0.165 7.5 45.4
Bangladesh 0.166 6.8 41.2
WORLD 20.42 1333.2 65.2
Sugarcane is a renewable, natural agricultural resource because it provides sugar, besides biofuel, fibre, fertilizer and myriad of by products/co-products with ecological
sustainability.

Sugarcane juice is used for making white sugar, brown sugar (Khandsari), Jaggery
(Gur) and ethanol. The main byproducts of sugar industry are bagasse and molasses.

5. 4
Molasses, the chief by-product, is the main raw material for alcohol and thus for
alcohol-based industries. Excess bagasse is now being used as raw material in the
paper industry. Besides, co-generation of power using bagasse as fuel is considered
feasible in most sugar mills.

6. 5
Growth morphology

Propagation

Stem cuttings or sections of the stalks
called "setts" or seed pieces propagate
sugarcane. Each sett contains one or
more buds. The buds, located in the root
band of the node, are embryonic shoots
consisting of a miniature stalk with small
leaves.

The outer small leaves are in the form of
scales. The outermost bud scale has the
form of a hood. Normally, one bud is
present on each node and they alternate
between one side of the stalk to the
other.

Variations in size, shape and ther characteristics of the bud provide a means of
distinguishing between varieties. Each sett also contains a circle of small dots above
the node, which are the root primordia. Each primordium exhibits a dark center, which
is a root cap, and a light colored "halo".

The bud sprouts under favourable conditions and gives rise to a primary stalk, whereas
from the primordial the sett roots originate.

During nearly one month after germination, that is, sprouting of the buds, the young
plant lives at the expense of the reserves present in the seed piece, and partially using
water and nutrients provided for by the first roots.

The Leaf
The leaf of the sugarcane plant is divided into two
parts: sheath and blade, separated by a blade joint.
The sheath, as its name implies, completely sheaths
the stalk, extending over at least one complete
internode.

The leaves are usually attached alternately to the
nodes, thus forming two ranks on opposite sides. The
mature sugarcane plant has an average total upper
leaf surface of about 0.5 square meter and the
number of green leaves per stalk is around ten,
depending on variety and growing conditions.

7. 6
The blade joint is where two wedge shaped areas called "dewlaps" are found. The
leaves are numbered by Kuijper's system, as quoted by Casagrande (1991). The first
leaf from top to bottom of the stalk with clearly visible dewlap is designated as +1.
Downwards they receive, in succession, the numbers +2, and +3. The "top visible
dewlap" leaf (+3) is a diagnostic tissue that is frequently used in the evaluation of the
nutritional status.

The Inflorescence

When a sugarcane plant has reached a
relatively mature stage of development,
its growing point may, under certain
photoperiod and soil moisture
conditions, change from the vegetative
to reproductive stage.

This means the growing point ceases
forming leaf primordia and starts the
production of an inflorescence. It is a
short day plant. Its photoperiodic
conditions can thus be attained largely
in the tropics.

The inflorescence, or tassel, of
sugarcane is an open-branched panicle
.It is also known as arrow. Therefore
flowering is also known as "arrowing".
Each tassel consists of several
thousand tiny flowers, each capable of
producing one seed. The seeds are
extremely small and weigh
approximately 250 per gram or 113,500
per pound.

For commercial sugarcane production,inflorescence
development is of little economic importance. Flowering is important for crossing and
producing hybrid varieties.

Generally, a day length close to 12.5 hours and night temperatures between 20° to
25°c will induce floral initiation. Optimum growth conditions in the vegetative phase
(fertile soil, abundant supply of nitrogen and moisture) restrict inflorescence while
stress conditions induce formation of blossoms.

8. 7
The Root System

In the commercial sugarcane crop,
which is asexually propagated,
development of the root system is
initiated soon after planting a
portion of stem (sett) with atleast
one lateral bud.

The first roots formed are sett
roots, which emerge from a band of
root primordia above the leaf scar
on the nodes of the sett.Sett roots
can emerge within 24 hours of
planting, although differences in
the time required for root
emergence occur among varieties.
Sett roots are fine and highly branched roots, which sustain the growing plant in the
first weeks after germination.

Shoot roots are second type of root, which emerge from the base of the new shoot 5-7
days after planting .The shoot roots are thicker and fleshier than sett roots and develop
in to the main root system of the plant. Sett roots continue to grow for a period of 6-15
days after planting, mostly senescing and disappearing by 60-90 days as the shoot
root system develops and takes over supply of water and nutrients to the growing
shoot. By the age of 3 months, sett roots comprise less than 2% of root dry mass.

Sett roots initially have an elongation rate of a few mm/day, reaching 20 mm/day within
a few days of germination under favourable conditions. Shoot roots grow more rapidly,
with maximum rates of elongation of up to 80 mm/day observed, though only for short
periods. Mean growth rates for shoot roots over 10 days were 40 mm/day in sandy
soils and 28 mm/day in heavy clay.

Mean rates of root penetration, or the rate of descent of the root system, of 20-30
mm/day were also reported. Root penetration in another trial was 20 mm/day down to
a depth of 1.6 m for rainfed crops, but slowed in irrigated crops to 17 mm/day in the
first 1.0 m and 6 mm/day between 1.0 and 1.6 m.

Genotypic variation in sugarcane root systems is well documented and those
producing many tillers normally produce many roots because each new tiller is a
source of shoot roots. Likewise cultivars with more horizontal (weak gravitropic) root
penetration are more resistant to lodging than those with strongly gravitropic root
system.

9. 8
A longitudinal section of a root tip consists mainly of four parts: the root cap, the
growing point, the region of elongation, and the region of root hairs. The root cap
protects the tender tissues of the growing point as the root pushes through the soil.
The growing point consists mainly of an apical meristem, where cell division takes
place.

In the region of elongation, the cells increase in size and diameter until they reach their
ultimate size. The region of root hairs is characterized by epidermal cells forming
outgrowths (hairs), which dramatically increases the root-absorbing surface.

Stalk

Stalk is also known as "millable cane". It develops from the bud of seed-cane. When
seed-cane is planted, each bud may form a primary shoot.

From this shoot, secondary shoots
called "tillers" may form from the
underground buds on the primary
shoot. In turn, additional tillers may
form from the underground
secondary shoot buds. The stalk
consists of segments called joints.

Each joint is made up of a node and
an internode. The node is where the
leaf attaches to the stalk and where
the buds and root primordia are
found. A leaf scar can be found at
the node when the leaf drops off the
plant. The length and diameter of
the joints vary widely with different varieties and growing conditions. The colors of the
stalk seen at the internodes depend on the cane variety and environmental conditions.

For example, exposure of the internodes to the sun may result in a complete change of
color. The same variety grown in different climates may exhibit different colors. All
colors of the stalk derive from two basic pigments: the red color of anthocynin and the
green of chlorophyll.

The ratio of the concentration of these two pigments produce colors from green to
purple-red to red to almost black. Yellow stalks indicate a relative lack of these
pigments. The surface of the internode, with the exception of the growth ring, is more
or less covered by wax. The amount of wax is variety dependent.

10. 9
The top of the stalk is relatively low in sucrose and therefore is of little value to the mill.
The top 1/3 contains, however, many buds and a good supply of nutrients, which
makes it valuable as seed cane for planting.

A cross section of an internode shows, from the outside to the center, the following
tissues: epidermis, cortex or rind, and ground tissue with embedded vascular bundles.
The cells of the rind are thick-walled and lignified. These cells help strengthen the
stalk. More toward the center, the ground tissue contains the vascular bundles with the
xylem and phloem.

Xylem tissue conducts water and its dissolved minerals upward from the roots, and
phloem conductive tissue transports plant- manufactured nutrients and products, for
the most part, downward toward the roots.

Two types of cracks are sometimes found on the surface of the stalk; harmless, small
corky cracks, which are restricted to the epidermis, and growth cracks which may be
deep and run the whole length of the internode.

Growth cracks are harmful since they allow increased water loss and expose the stalk
to disease organisms and insects. Growth cracks are dependent on variety and
growing conditions.

11. 10
Crop growth phases

Germination and Establishment Phase
• The germination phase is from
planting to the completion of
germination of buds.
• Under field conditions germination
starts from 7 to 10 days and
usually lasts for about 30-35 days.
• In sugarcane, germination denotes
activation and subsequent
sprouting of the vegetative bud.
• The germination of bud is
influenced by the external as well
as internal factors.
• The external factors are the soil
moisture, soil temperature and
aeration.
• The internal factors are the bud
health, sett moisture, sett reducing
sugar content and sett nutrient
status.
• Optimum temperature for sprouting
is around 28
o
-30
o
c .Base
temperature for germination is
about 12
o
. Warm, moist soil ensures rapid germination.
• Germination results in an increased respiration and hence good soil aeration
are important.
• Therefore open structured porous soils facilitate better germination.
• Under field conditions, about 60 per cent germination can be considered safe
for raising a satisfactory crop.

Tillering Phase
• Tillering starts from around 40 days after planting and may last up to 120 days.
• Tillering is a physiological process of repeated under ground branching from
compact nodal joints of the primary shoot.
• Tillering provides the crop with appropriate number of stalks required for a good
yield.
• Various factors viz., variety, light, temperature, irrigation (soil moisture) and
fertilizer practices influence tillering

12. 11
• Light is the most important external factor influencing tillering. Adequate light
reaching the base of the sugarcane plant during the tillering period is of
paramount importance.
• Temperature around 30
o
c is considered optimum for tillering. Temperature
below 20
o
retards tillering.
• Early formed tillers give rise to
thicker and heavier stalks. Late
formed tillers either die or
remain short or immature.
• Maximum tiller population
reaches around 90-120 days
after planting. By about 150-
180 days, atleast 50 per cent
of the shoots die and a stable
population is established.
• Cultivation practices such as
spacing, time of fertigation,
water availability and weed
control influence tillering.
• Though 6-8 tillers are produced from a bud, ultimately only 1.5 to 2 tillers per
bud remains to form canes.
• Ratoon crop gives much higher and early tillering than a plant crop.
• Encouraging good tillering is important to build adequate population.
Grand Growth Phase
• Grand growth phase starts from 120 days after planting and lasts up to 270
days in a 12-month crop. During the early period of this phase tiller stabilization
takes place. Out of the total tillers
produced only 40-50% survive by 150
days to form millable cane.
• Most important phase of the crop wherein
the actual cane formation and elongation
and thus yield build up takes place.
• Leaf production is frequent and rapid
during this phase with LAI reaching around
6-7.
• Under favourable conditions stalks grow
rapidly almost 4-5 internodes per month.
• Drip irrigation, fertigation and warm, humid
and sunny climatic conditions favour better
cane elongation. Moisture stress reduces
internodal length. A temperature around 30
o
c with a humidity of around 80% is
most conducive for good growth.

13. 12
Ripening and Maturation Phase
• Ripening and
maturation phase in a
twelve-month crop
lasts for about three
months starting from
270-360 days.
• Sugar synthesis and
rapid accumulation of
sugar takes place
during this phase and
vegetative growth is
reduced.
• As ripening advances,
simple sugars
(monosaccharide viz., fructose and glucose) are converted into cane sugar
(sucrose, a disaccharide).
• Cane ripening proceeds from bottom to the top and hence bottom portion
contains more sugars than the top portions.
• Ample sunshine, clear skies cool nights and warm days (i.e., more diurnal
variation in temperature) and dry weather are highly conducive for ripening.
Practical Implications
• Better understanding of what is going on in the plant
• This understanding aids in efficient water and nutrient management
• Control of vegetative growth and manipulation of sugar production to some
extent is possible
• Knowledge of phenological growth phases is essential for maximizing cane
yields and sugar recovery
Climate

Sugarcane is grown in the world from alatitude 36.7° N and 31.0° S, from sea level to
1000m of altitude or little more. It is considered as essentially a tropical plant. It is a
long duration crop and thus it encounters all the seasons' viz., rainy, winter and
summer during its life cycle.

Principal climatic components that control cane growth, yield and quality are
temperature, light and moisture availability. The plant thrives best in tropical hot sunny
areas. The "ideal" climate for production of maximum sugar from sugarcane is
characterized as:

14. 13
• A long, warm growing season with a high incidence of solar radiation and
adequate moisture (rainfall) - the plant uses from 148 to 300g of water to
produce 1.0g of dry substance.
• A fairly dry, sunny and cool, but frost free season for ripening and harvesting -
moisture percentage drops steadily throughout the life of the sugarcane plant,
from 83% in very young cane to 71% in mature cane, meanwhile sucrose grows
from less than 10 to more than 45% of the dry weight.
• Freedom from typhoons and hurricanes
Rainfall: A total rainfall between 1100 and 1500 mm is adequate provided the
distribution is right, abundant in the months of vegetative growth followed by a dry
period for ripening. During the active growth period rainfall encourages rapid cane
growth, cane elongation and internode formation. But during ripening period high
rainfall is not desirable because it leads to poor juice quality, encourages vegetative
growth, formation of water shoots and increase in the tissue moisture. It also
hampers harvesting and transport operations. This seems to be the case in regions
of South America, South East Asia and some parts of Southern India.
Temperature: Growth is closely related to temperature. Optimum temperature for
sprouting (germination) of stem cuttings is 32° to 38°c. It slows down below 25°,
reaches plateau between 30°-34°, is reduced above 35° and practically stops when
the temperature is above 38°.Temperatures above 38° reduce the rate of
photosynthesis and increase respiration. For ripening, however, relatively low
temperatures in the range of 12° to 14° are desirable, since this has a noticeable
influence on the reduction of vegetative growth rate and enrichment of sucrose in
the cane. At higher temperatures reversion of sucrose into fructose and glucose
may occur besides enhancement of photorespiration thus leading to less
accumulation of sugars. Severe cold weather inhibits bud sprouting in ratoon crop
and arrests cane growth. Temperatures lower than 0°C induces freezing of less
protected parts such as young leaves and lateral buds. The damage depends upon
the length of the cold period. Smut initiation and spread is high at ambient
temperatures of 25° -30°. Similarly the spread of red not disease is high at higher
temperatures (37°-400°) when all other conditions are similar. Rust incidence is
high when the minimum temperatures are drastically reduced. Shoot-fly incidence
is high in summer when the air temperatures are very high. Also higher shoot fly
incidence was observed when the difference between maximum (day) and
minimum (night) temperature are low.
Relative humidity: High humidity (80-85%) favours rapid cane elongation during
grand growth period. A moderate value of 45-65% coupled with limited water supply
is favourable during the ripening phase.

15. 14
Sunlight:

Sugarcane is a sun loving plant. It grows well in areas receiving solar energy from
18 - 36 MJ/m
2
. Being a C4 plant, sugarcane is capable of high photosynthetic rates
and the process shows a high saturation range with regards to light. Tillering is
affected by intensity and duration of sunshine. High light intensity and long duration
promote tillering while cloudy and short days affect it adversely. Stalk growth
increases when daylight is within the range of 10 - 14 hours. Increase in leaf area
index is rapid during 3rd to 5th month, coinciding the formative phase of the crop
and attained its peak values during early grand growth phase (Ramanujam and
Venkataramana, 1999).

Optimum climatic requirements:
Mean total radiation received in 12 months of
growth has been estimated to be
around 6350 MJ/m
2
. About 60%
of this radiation was intercepted
by the canopy during formative
and grand growth periods. The
total dry matter production
showed linear relationship with
the intercepted PAR and the test
of correlation yielded R
2 value of
0.913 (Ramanujam and
Venkataramana, 1999). However,
the energy conversion rate in
terms of dry matter production
per unit of intercepted radiation
showed a quadratic response
with percent light interception indicating that the rate of energy conversion
increased linearly up to 50% light interception and beyond this level, the rate of
photosynthetic conversion of solar radiation gets reduced (Ramanujam and
Venkataramana, 1999). In sugarcane crop canopy the upper 6 leaves intercept

16. 15
70% of the radiation and the photosynthetic rate of the lower leaves decreased due
to mutual shading. Therefore, for effective utilization of radiant energy a LAI of 3.0 -
3.5 is considered optimum. Areas having short growing period benefit from closer
spacing to intercept high amount of solar radiation and produce higher yields. But in
areas with long growing season wider spacing is better to avoid mutual shading
and mortality of shoots. Rough estimates show that 80% of water loss is associated
with solar energy, 14% with wind and 6% with temperature and humidity. High wind
velocities exceeding 60-km/hour are harmful to grownup canes, since they cause
lodging and cane breakage. Also, winds enhance moisture loss from the plants and
thus aggravate the ill effects of moisture stress.
Effect of climate on sugarcane yields and sugar recovery:
The sugarcane productivity and juice quality are profoundly influenced by weather
conditions prevailing during the various crop-growth sub-periods.
Sugar recovery is highest when the weather is dry with low humidity; bright
sunshine hours, cooler nights with wide diurnal variations and very little rainfall
during ripening period. These conditions favour high sugar accumulation.

Soil Requirement

Soil is a medium for plant growth. It provides nutrients, water and anchorage to the
growing plants. Maintenance of proper physical, chemical and biological conditions of
the soil is necessary for realizing higher growth, yield and quality of sugarcane.
Sugarcane does not require any specific type of soil as it can be successfully raised on
diverse soil types ranging from sandy soils to clay loams & heavy clays.

A well drained, deep, loamy soil with a bulk density of 1.1 to 1.2 g/cm
3
(1.3-1.4 g/cm
3
in
sandy soils) and total porosity, with an adequate balance between pores of various
sizes, is higher than 50%; ground water table below 1.5 to 2.0 m from soil surface and
an available water holding capacity of 15% or more (15 cm per meter depth of soil is
considered ideal for sugarcane cultivation).

The optimum soil pH is about 6.5 but sugarcane can tolerate considerable degree of
soil acidity and alkalinity. Hence, it is found growing in soils with pH in the range of 5 to
8.5. Liming is required if pH is less than 5.0, or gypsum application if pH is more
than 9.5. Nematode infestations are likely to occur in very sandy soils.

Soil testing before planting is desirable as it helps in determining the optimum quantity
of macro and micro nutrient application. Chemical constraints in the soils, such as
acidity and low fertility, are relatively easy to correct or control.

17. 16
Poor physical conditions like soil compaction due to intense mechanization when
limiting, are much more difficult to ameliorate. For this reason, physical properties of
soil are given as a factor in sugarcane growth. Based on the experience gained in
Brazil, a few criteria to define soils, which are apt for sugarcane growing, were
suggested (Table 2).

Table 2. Criteria to Classify the Aptitude of Soils for Growing Sugarcane

Class
Characteristics
Good Average Restricted Unfit
Effective depth Deep Medium Shallow Too shallow
Soil texture Clayey Medium to clayey Sandy Too sandy
Relief Flat Rolling Too rolling Hilly
Fertility High Medium or low Too low Too low
Drainage Good Medium to
accentuated
or incomplete
Incomplete Excessive or
deficient
Restraints to
mechanization
Absent Medium Strong Too strong
Susceptibility
to erosion
Low Medium High Too high
Source: Kofeler and Bonzelli (1987)


Management of compacted soils
Problem of sub-surface hard pans or compaction is a common phenomenon in
intensive mechanization, more number of ratoons and sugarcane - rice rotation
systems.

Effects of Soil Compaction
• Increases bulk density (Light to medium soils: 1.5 to 1.7 g/m
3
and Heavy soils:
1.45 to 1.57 g/m
3
) and soil penetration resistance
• Reduction in porosity, infiltration rates, and water storage capacity
• Impedance to root penetration and proliferation. Shallow root system makes the
plant susceptible to drought during dry spells.
• Reduced nutrient and water uptake
• Promotes lodging particularly in unusually wet conditions
Ameliorative Practices
• Deep ploughing, sub-soiling or chiseling up to a depth of 50 - 75 cm at 90 cm
• Application of organic manures (FYM at 25 tons/ha), growing of green manure
crops and turning them into soil
• Incorporation of gypsum at 5 tons/ha

18. 17

Management of Acid Soils
Usually acid soils are found in high rainfall areas and in soils where organic matter
content is high. Soil acidity adversely affects sugarcane growth, yield and quality.
Under acidic conditions, the adverse effects are due to aluminium, iron and
manganese toxicity. Aluminium toxicity can cause P deficiency symptoms due to
precipitation of alumino-phosphate complexes with in the plant and in the soil. In
Australia, Ca deficiency is associated with Al toxicity on acid soils.

In acid soils conditions (pH less than 5.2), Al replaces Ca on cation exchange capacity.
Aluminium toxicity may occur on mineral soils when Al occupies greater than 30% of
the cation exchange capacity.

In sandy soils
having a very low
cation exchange
capacity, lower
concentrations of Al
in the soil solution
may cause toxicity
problems. High
applications of K
may induce Ca
deficiency in acid
soil containing low
Ca levels (Photo
Source: Anderson
and Bowen, 1990).

Root growth, tillering, shoot elongation and LAI are severely affected due to the above
nutritional disorders thus causing poor cane yield and juice quality.

On acid soils in Brazil, better root development deeper in the soil horizon has been
noticed when gypsum is used. Liming is the most important practice in the acid soils to
improve productions.

The General Lime Requirements as Follows.
• Sandy soils 450 - 675 kg/ha every 2 years
• Clay loams 1800 - 2250 kg/ha every 3 - 4 years
• Clay soils 2700 - 3600 kg/ha every 4 - 5 years.
• Bone meal and rock phosphates are well suited to acid soils to supply
phosphorous

19. 18
Management of Soil Salinity and Sodicity
The saline and sodic soils are wide spread in sugarcane growing areas of the world. A
soil with electrical conductivity below 2 dS/m, by and large, does not affect the growth
appreciably. Sugarcane is moderately sensitive to soil salinity. The decrease in crop
yield varies with the level of soil salinity (Photo Source: Anderson and Bowen, 1990).

The decrease in crop
yield is 0% at an ECe of
1.7 dS/m, 10% at 3.3,
25% at 6.0, 50% at 10.4
and 100% at an ECe of
18.6 dS/m. Soil salinity
also adversely affects
sheath moisture content
and nitrogen content.

Likewise, SAR more
than 20 caused 50%
yield reduction. Increase
in exchangeable sodium
percent from 14.4 to 23.5 lead to reduction in cane (9 - 26%) and sugar yield (12 -
29%) in 10 sugarcane cultivars studied at Karnal, India.

Varieties differ in their responses to soil salinity and acidity. Germination and early
growth stages are more sensitive than later stages of crop growth. Ratoon crop is
more sensitive to salinity than plant crop.

Symptoms of Soil Salinity and Sodicity
• Stunted growth and necrotic leaves with scorched tips and margins
• Poor tillering and root growth
• Reduction in internodal length and girth of cane
• Impaired cane quality with reduced juice purities
• Problems in processing for jaggery and sugar
Ameliorative Measures
• Growing of slat tolerant varieties
• Manipulation of soil environment by reclamation and drainage
• Adoption of drip irrigation to maintain higher soil water potential in the root zone
by light and frequent irrigations

20. 19

Drip Irrigation Features

Introduction
Drip irrigation in
sugarcane is a
relatively new
innovative
technology that can
conserve water,
energy and
increase profits.
Thus, drip irrigation
may help solve
three of the most
important problems
of irrigated
sugarcane - water
scarcity, rising
pumping (energy)
costs and
depressed farm
profits.





Surface Drip Subsurface Drip

Whether or not drip will be successful depends on a host of agronomic, engineering
and economic factors. "Drip irrigation is defined as the precise, slow and frequent
application of water through point or line source emitters on or below the soil surface at

21. 20
a small operating pressure (20-200 kPa) and at a low discharge rate (0.6 to 20 LPH),
resulting in partial wetting of the soil surface.

In the literature, "trickle" is used interchangeably with "drip". Most popular drip versions
used in sugarcane are surface and subsurface drip.
• Surface Drip: The application of water to the soil surface as drops or a tiny
stream through emitters placed at predetermined distance along the drip lateral
is termed as surface drip irrigation. It can be of two types - online or integral
type surface drip system. Integral dripline is recommended for sugarcane.
• Subsurface Drip (SDI): The application of water below the soil surface through
emitters molded on the inner wall of the dripline, with discharge rates (1.0 - 3.0
LPH) generally in the same range as integral surface drip irrigation. This method
of water application is different from and not to be confused with the method
where the root zone is irrigated by water table control, herein referred to as
subirrigation. The integral dripline (thin or thick-walled) is installed at some
predetermined depth in the soil depending on the soil type and crop
requirements. There are two main types of SDI - "one crop" and "multicrop".
Adoption of drip irrigation (surface or subsurface) system in sugarcane cultivation is
technically feasible, economically viable and beneficial in many ways:
• Higher water application uniformity
• Deceased energy costs due to reduced pumping time to irrigate a given design
area
• Saving in water up to 45 to 50% contributing to higher water use efficiency
• Saving in fertilizer (25 to 30%) due to fertigation consequently improved fertilizer
use efficiency i.e., agronomic efficiency, physiological efficiency and apparent
recovery fraction
• Less weed growth and saving in labour due fewer weed control, fertigation &
plant protection operations
• Less pest & disease incidence due to better field sanitation
• Optimum soil water air relations contributing to better germination, uniform field
emergence and maintenance of optimum plant population
• Early harvesting and more ratoons
• Day/Night irrigation scheduling is possible
• Facilitates growing of crop on marginal soils due to frequent irrigations and
fertigation
• High frequency irrigation, micro-leaching and higher soil water potential enables
use of saline water for irrigation
• Higher cane and sugar yields

22. 21
Effective drip technology requires a more intense application of crop, soil, climatic,
engineering, and economic factors than is usually present with furrow irrigation. New
management perspectives and skills are required t planting configuration, land
preparation, drip design features, irrigation scheduling, fertigation, operation &
maintenance of the system.

The new management practices induced with drip technology seem to have
significantly helped increase cane and sugar yields. Planting configuration and drip
design features will be dealt in this section while others will dealt in different sections.

Planting Configuration
Widely followed sugarcane planting systems are viz., ridge and furrow system in
tropical region and flat system in sub-tropical region. The spacing of crop rows ranges
from 0.60 m to 1.5 m. The most common spacing followed is 0.90 m in ridge and
furrow system as shown in Fig, because it facilitates easy irrigation and solid support
when proper earthing up is done.

However, when the crop is raised under drip method of irrigation modifying the
conventional ridge and furrow planting system to a paired-row or dual row system
without sacrificing the plant population per unit area proved to be physiologically
efficient and cost effective.

The spacing of paired-rows is dependent upon the soil type and planting season.
Wider spacing is advisable in fine textured soils under high fertility conditions and for
long duration crop (> 13 to 16 months) and high tillering varieties. While in coarse
textured soils with poor soil fertility status, short season crop (10-12 months) and shy
tillering varieties narrow spacing is desirable.

The paired-row planting pattern and associated spacing requirements both under
surface and subsurface drip irrigation are depicted in the picture.
These planting patterns are for guidance only. If necessary, adjustments in planting
patterns may have to be made depending upon the variety, planting season, and
fertility status and soil textural conditions of the region.

Drip Design Guidelines - Summary
The summary of drip guidelines recommended for sugarcane in different countries
based on varietal characteristics, soil type, management, cost-effectiveness, and a
local condition is given in Table 3.

Table 3. Sugarcane: Drip Design Guidelines
Distance (m)
Planting
pattern
Drip
system
Two
rows of
a pair
Two
paired
rows / two
Two
driplines
Dripline
installation
depth (cm)
Emitter
distance
(m)
Discharge
(LPH)

23. 22
rows
Single row Surface --- 1.2 to 1.5 1.2 to 1.5 --- 0.4 to 0.6 1.0 to 3.0
Paired row Surface 0.4 to 1.0 1.4 to 2.0 1.8 to 2.5 --- 0.4 to 0.6 1.0 to 3.0
Paired row SDI 0.4 to 1.0 1.4 to 2.0 1.8 to 2.5 0.15 to 0.30 0.4 to 0.6 1.0 to 2.3

Design of Drip Irrigation Scheme
Drip irrigation offers the grower the potential for increasing cane yields & quality; and
opportunity for improving irrigation & energy efficiencies in irrigated sugarcane.
However, to realize this potential and opportunity, drip irrigation schemes must be
designed, installed and managed correctly.

Design Factors
The main technical factors that should be considered when designing a drip irrigation
scheme for sugarcane are as follows:
• Peak crop water requirements
• Area of fields to be irrigated
• Availability of irrigation water and power
• Irrigation water quality
• Soil characteristics
• Land topography
Components of a Drip Irrigation System
The pictures shows the main components of a drip irrigation system.



Agronomic Advantages of Drip Over Sprinkler & Furrow Irrigation

System Capacity
Drip irrigation system must have a design capacity adequate to satisfy the peak crop
water requirement of the crop to be irrigated within the design area. The capacity shall
include an allowance for water losses that may occur during application periods. The
system shall have the capacity to apply a stated amount of water in the design area in

24. 23
a specified net operation period. The system should have a minimum design capacity
sufficient to deliver the peak daily crop water requirements in about 90% of the time
available or not more than 22 h of operation or not more than the power availability
period per day.

Operating Pressure
The design operating pressure shall be in accordance with the recommendations of
the manufacturer. The system operating pressure must compensate for pressure
losses through system components and field elevation effects.

Equipment Selection Control Head
The control head station includes facilities for water measurement, filtration &
treatment, injection of fertilizers & chemicals, flow and pressure control, timing of
application and backflow prevention.

Filtration System
Filtration system is the assembly of independently controlled physical components
used to remove suspended solids from irrigation water. Filtration of irrigation water is
vital for drip irrigation schemes in order to avoid blockage of emitters as the internal
passages of emitters are very small.

The choice of filter depends mainly on the kind of impurities contained in the water and
the degree of filtration required on the emitter. It is recommended that Netafim expert
advise is sought on water quality analysis for pH, suspended solids, dissolved solids
and bacterial population. Filtration system design recommendations should include
location, size, specification of allowable suspended material sizes, types of filters, and
maintenance requirements.
Location: A primary filter shall be located after the pump and fertigation unit to remove
both large and fine particles from the flow. Secondary filters may be used downstream
from the primary filter to remove any particles, which may pass through the primary
filter during normal or cleaning operations. When secondary filters are used, the size of
the openings is usually larger than that of the primary filter to minimize needed
attention.

Size: Filter flow openings shall be sufficiently small to prevent the passage of
unwanted particles into the system. The filter size should be based on the diameter of
the emitter opening or the type and size of contaminants to be filtered. The capacity of
the filter should be sufficiently large to permit the rated flow without frequent cleaning.
Filters that are to be cleaned by hand should not require more than daily maintenance.
The size should be the most economical with the lowest friction losses ranging from
0.3 to 0.5 bars.

Types: Filtration may be accomplished through the use of different types of filters viz.,
screen (for inorganic impurities and moderate quality water or following a primary

25. 24
filtration with sand or disc filters) disc (for removal of impurities of organic and
inorganic origin, algae included), hydrocyclones (for separation of sand or silt from well
or river water) and media or sand filters (for open wells, open reservoirs, streams etc).

Fertigation Unit
Drip irrigation systems provide a convenient method of applying fertilizers and
chemicals with the irrigation water using special fertigation devices. The fertigation
devices include pressure differential systems (fertilizer tank), suction produced by a
venturi principle (venturi injectors) and pumps (diaphragm or piston or electrically
operated). The fertilizer unit is an integral part of control head.

The important considerations are injection method & rate, concentration, storage tank
capacity, contamination of water supply, reliability and accuracy of operation, warranty
and service, automation suitability, field performance, price including acquisition and
maintenance cost, life expectancy etc

Water Carrier System - Supply Lines, Main Lines and Submains
The design objective of supply lines, main lines and submains is to deliver the
required, pressurized quantity of water to the laterals (driplines) as efficiently as
possible. The cane grower should attempt to minimize the total cost of the supply lines
and mainlines needed to meet the engineering specifications.

Sub-main pipe should be based upon capacity requirement, maintenance cost,
investment cost and pressure uniformity. Buried pipelines are less subject to damage
than surface lines and do not require special handling during the crop season.
Appropriate risers and valves exist for each kind of pipe. Supply lines, main lines and
submains generally account for 20-35% of total investment cost/ha.

Riser Assembly
Connected to the water carrier system and located at each field block is a riser
assembly. Typically, this will consist of a control valve, a disc filter, a pressure relief
valve and pressure regulator, a water pressure test point, and an air release valve.

The volume of water applied to each field block is controlled by the opening and
closing of valves. These can be simple gate valves, semi-automatic volumetric valves
or automatic solenoid valves connected back to a central controller. Although semi-
automatic and automatic systems reduce labour running costs and facilitate night-time
irrigation, they are more expensive. It is recommended, wherever possible, that cane
growers choose the simplest control systems and systems that are easy to use and
easy to maintain.

The air relief valve, which may also act as a water pressure test point, is necessary to
prevent water hammers whenever air is escaping from the water carrier system. The

26. 25
discharge of driplines other than those with pressure compensating emitters is
dependent on the water pressure in the dripline.

The pressure regulator at the riser is used to maintain water pressure in the driplines at
the level recommended by the Netafim design engineer. It should be noted that riser
assemblies should be protected from damage through vandalism, cane fires and infield
operations such as mechanical harvesting, loading etc. A concrete box with a metal
door usually provides sufficient protection.


Dripline Type

In most sugarcane drip irrigated systems water is conducted from the riser assembly
into a sub-main into which the driplines are connected. Although there are many
different types of Netafim driplines that are used in sugarcane, they are all designed to
distribute water uniformly over the entire design area of a given field block. A variation
in discharge rate from dripline emitters that is acceptable is of the order of
± 8-10%.

Driplines vary in emitter design, quality, uniformity of discharge and cost. From the
outside, most integral driplines look alike. Yet there are major differences between
products, particularly emitters. Consistent and superior performance of an integral
dripline lies in the quality of its emitter. Several years of experience has shown that the
following factors should be considered when selecting a dripline that is to remain either
on surface or buried throughout a complete life cycle of a plant cane and 2 to 8
ratoons.

27. 26
Technical Factors
• Precision-molded emitters for uniform and constant low discharge of water &
nutrients
• Wider and deeper flow path cross section for clog free discharge of water
• Sharp teeth for increased turbulence, flow control & flushing the emitter
• Seamless pipe construction for maintaining greater tensile and burst strength
facilitating higher operation pressures for longer runs
• Raised filter inlet emitter for drawing clean water from the pipe center to prevent
clogging
• Emitters with filters to prevent plugging, less maintenance & longer life.
• Flexible emitter spacing and choice of flow rates to suit different sugarcane
varieties, planting patterns, soil types etc.
• Low emitter exponent and manufacturing coefficient of variation
• Flow rate insensitive to temperature differences
• Insect resistance, resistance to sunlight, no moving parts and anticipated life
• Driplines come in a range of wall thicknesses. Construction and wall thickness
of the dripline should be sufficient to reduce the risk of the pipe being crushed or
pinched by cane stools or roots or by in-field traffic such as mechanical loaders,
farm machinery etc. Recommended successful driplines are given in Table 4:
• Flap mechanism to prevent the risk of sucking of fine soil material into the
dripline emitters leading to plugging
• Nominal diameters are 16 mm and 22mm. A larger diameter will allow the
supply of water to a greater length of dripline before pressure drops below
design requirements. This results in saving in the cost of submains.
• Availability of machinery to recover the driplines at the end of the crop cycle and
used for a second crop cycle if possible after refurbishment
Table 4. Recommended Driplines for Sugarcane
Dripline thickness Category Crop type
34 mil (0.8 mm) - 47 mil




(1.2 mm)
Thickwalled &




PC or Non PC
For surface and subsurface drip, rougher
soil conditions and where insect damage is
expected. Lasts 10+ years with proper
operation and maintenance techniques
12 mil (0.3 mm) - 25 mil


(0.63 mm)
Thinwalled &



PC or Non PC
For subsurface drip and good soil
conditions. Lasts for 3-5 years.

Agronomic Factors
• Both surface and subsurface drip irrigation system were technically feasible in
sugarcane under diverse conditions

28. 27
• Availability of dripline types for application in sugarcane viz., thick-walled for
surface drip irrigated cane, thin-walled for subsurface drip irrigated cane, non-
pressure compensated driplines for leveled land, pressure compensated
driplines for undulated topography etc
• Subsurface drip irrigation was superior over surface drip in terms of water
availability, uniformity, water use, water use efficiency, cane yield and quality,
management etc
• Paired row or dual row or pineapple planting configuration with variable
spacings depending upon the soil texture with one dripline for every two rows
was found to be technically feasible, economically viable and potentially
profitable in comparison to rectangular single row planting configuration with
dripline for every crop row.
• Driplines can be successfully buried before planting cane with out waiting for
planting and germination of cane.
• Cane germination and field emergence was adequate to give satisfactory plant
stand both under surface and SDI systems with out any supplementary use of
surface furrow or overhead sprinkler system for germination irrigation
Emitter Spacing, Discharge Rate and Depth of Placement
The area wetted as a percent of the total crop area i.e., wetting patterns that are
obtained under drip irrigation depend on a number of factors which include the soil
hydraulic properties, emitter spacing, dripline placement with respect to the cane rows,
emitter discharge rate, planting configuration, crop evapotranspiration and irrigation
regime. The following information concerning wetting patterns has been obtained by
Netafim Agronomists & Design Engineers from several years of experimentation and
experience under diverse agro-ecological conditions:
• Emitter Spacings: Spacings of 0.3 to 0.75 m and discharge rates of 1.0 to 3
LPH were acceptable to most soil types on which sugarcane is grown in
different countries today. It is recommended, however, that the lower discharge
rates and closer emitter spacings are used on light textured sandy, loamy
sands, sandy loams, which have low water retention capacities. Conversely
higher discharge rates and wider emitter spacings are recommended for
medium to heavy textured soils viz., loamy, silty clay, clay loams and clays.
Emitter discharge rate should not create runoff within the immediate application
area. In fields with varying soil types, this criterion shall apply to the soil with the
lowest infiltration rate unless it is less than 15% of the area irrigated. It should
be noted that wider the spacing between emitters the more difficult it is to
achieve uniform wetted strip and in turn uniform cane germination and field
emergence.

29. 28
• Wetted Area: The area wetted as a percent of the total cane cropped area
ranged from a low of 28% in widely spaced paired-row planting configuration
with dripline for every two rows (placed midway in between two rows) to a high
of 60% in single-row rectangular planting configuration with dripline for each
row.
• Depth of Placement: Subsurface dripline placement is the most popular
technique used in cane. Driplines buried underground are protected from
mechanical damage. Depth of placement is critical to optimize the potential for
drip irrigation. Soil type and topography dictates depth of placement. Light
textured soils (sandy, loamy sand and sandy loam) require shallow depth of
dripline placement so that water is not lost by deep percolation. Medium to
heavy textured soils (loamy, silty loam, clay loam & clay) which will wet-up
laterally (larger wetted diameter) can have deeper placement.
This is an advantage in minimizing damage to dripline from insects and rats and
intrusion of roots; it also allows planting over the top of the dripline. In sloping
blocks dripline placement can be offset to the uphill side of the sett so that water
will gravity drain to the root zone but care must be taken to avoid damage
during cultivation. The overall aim when considering dripline placement is to
maintain the most efficient supply of water to the effective root zone of the plant
under the conditions of soil type, soil depth, topography and any other limiting
conditions (Table 5). Shallow depth can cause crushing of driplines by
mechanical loaders and cane fires. Shallow depth of installation of driplines may
also lead to irrigation water being lost to direct soil evaporation as a result of
puddles formed above the driplines during irrigation. Try not to allow water to
reach the soil surface as it will allow germination of weed seeds. In dry
conditions it will be beneficial to wet-up to the surface after harvest to assist in
ratooning.
Table 5. Depth o Placement of Dripline in SDI System
SSooiill
tteexxttuurree
PPllaacceemmeenntt
ddeepptthh bbeellooww
ggrroouunndd
RReemmaarrkkss

LLooaammyy
ssaanndd &&
SSaannddyy
llooaamm

1155 ttoo 2200 ccmm

TThheessee ssooiillss bbeenneeffiitt ffrroomm sshhoorrtt && ffrreeqquueenntt
iirrrriiggaattiioonnss.. IIrrrriiggaattee ttoo rreeffiillll tthhee ssooiill pprrooffiillee ttoo
eeffffeeccttiivvee rroooottiinngg ddeepptthh oonnllyy.. NNoottee tthhaatt ddrriipp
iirrrriiggaattiioonn wweettss oonnllyy aa nnaarrrrooww bbaanndd uunnddeerr tthhee
ddrriipplliinnee iinn tthheessee ssooiillss aanndd tthhee ssttoorraaggee
ccaappaacciittyy ooff tthhee ssooiill iiss ssmmaallll..
SSiillttyy llooaamm
&& CCllaayy
llooaamm

2200 ttoo 2255 ccmm

LLeessss ffrreeqquueenntt iirrrriiggaattiioonnss,, llaarrggeerr vvoolluummee ooff
iirrrriiggaattiioonn wwaatteerr aapppplliiccaattiioonn ccaann bbee aalllloowweedd
ssiinnccee wwaatteerr sspprreeaaddss llaatteerraallllyy mmoorree iinnttoo tthhee
rroooott zzoonnee.. WWaatteerr ssttoorraaggee ccaappaacciittyy ooff tthhee
ssooiillss iiss hhiigghh..

30. 29


CCllaayy ssooiill


2255 ttoo 3300 ccmm

LLeessss ffrreeqquueenntt,, lloonnggeerr iirrrriiggaattiioonn ccyycclleess aanndd
llaarrggeerr vvoolluummee ooff iirrrriiggaattiioonn wwaatteerr aapppplliiccaattiioonn
ccaann bbee aalllloowweedd ssiinnccee wwaatteerr sspprreeaaddss llaatteerraallllyy
mmoorree iinnttoo tthhee rroooott zzoonnee.. WWaatteerr ssttoorraaggee
ccaappaacciittyy ooff tthhee ssooiillss iiss vveerryy hhiigghh.. HHoowweevveerr,,
wwaattcchh ffoorr iillll--ddrraaiinneedd ccoonnddiittiioonnss aanndd
wwaatteerrllooggggiinngg iinn tthhee ccrroopp rroooott zzoonnee..

Economic and Managerial Design Factors
The main managerial and economic factors that should be considered when designing
a SDI for sugarcane are as follows:
• Potential yield and CCS increment
• Cost of subsurface drip irrigation system
• Cost of installation and interest rate
• Operation and maintenance costs
• Availability and cost of water
• Availability and cost of trained skilled staff to operate the drip scheme
• Price of sugar
Other Factors
• Water - Source, availability and quality evaluation for determining filtration
system type, maintenance of irrigation system, crop management and selection
of fertilizers
• Soil evaluation for fertility status, clay content, CEC, bulk density etc for
determining the fertigation programme
• Determination of moisture holding properties and evaporative demand of the
atmosphere for irrigation scheduling
• Contour survey for selection of dripline type (pressure compensating or non-
pressure compensating), to determine dripline length and sub-main spacing
• Soil characteristics for determining appropriate emitter spacing and depth of
dripline placement
Installation
• It is essential that high quality installation and maintenance is adopted for
dripline which is installed below ground. The following points are important
when installing a system:Follow the Netafim Design Engineer instructions
scrupulously, for example when glueing PVC pipes, installing mains & submains
as pipe sizes will have been dimensioned to enable specified flow rates and
pressure throughout the system.
• After installation, check each part of the system carefully for leaks as these will
cause pressure problems at the tail end of the scheme

31. 30
• Check every dripline being injected for correct placement, orientation and depth
and to ensure there is no crimping of the riser, which connects dripline to the
submain.
• Bury mains and submains to ensure that rocks in the back fill do not damage
pipes.
• After hook-up, partially backfill portions of submains and pressure test before
completely backfilling trenches.
• Flush out the water carrier system to remove extraneous material before riser
assemblies and driplines are connected.
• Check water pressure at the risers and dripline flow rates: if these are not
according to the specification there has been a problem at either the design or
the installation stage.
Dripline Monitoring
Driplines and emitters, for both surface and subsurface systems, are subject to
plugging and breaking with passing time. Microbial and inorganic deposits are the two
principal causes of emitter plugging. Algae and bacterial slimes are of particular
concern when water is pumped directly from an irrigation ditch, reservoir, open well, or
natural channel. Even with sand media filters, microorganisms may grow in the lines
and become a major problem.

Maintaining a pH of 6.5-6.8 with periodical acid injection reduces precipitation of
inorganic compounds (phosphates, calcium, bicarbonates) and discourages algae
growth. Chlorine, also, may be used to treat algae. Shock treatments, with acids
(sulphuric, hydrochloric and phosphoric), which periodically reduce pH to 2-3 also kill
algae and eliminate some inorganic plugging.

Acidified fertilizers are used or are being developed to deal with emitter plugging.
Rodents, rabbits, and coyotes may chew holes in driplines, roots may clog subsurface
emitters, or lines may be mechanically damaged. For the most part, drip irrigated cane
growers world over have nor found these to be major problems. Broken or damaged
lines (from all causes) have affected less than 4% of the total system. Broken lines are
usually easily and inexpensively repaired.

Chemicals (like Trifluralin) help keep roots from clogging emitters under SDI. And
subsurface driplines are better protected from mechanical as well as rodent damage
with deeper line placement and more careful machinery operation in the field.

Improved Varieties

Variety is the pivot around which entire production system revolves. Therefore,
scientific sugarcane cultivation must start with choosing an appropriate variety for the

32. 31
agro-climatic zone, soil type and season concerned. Improved varieties are now
available for almost all the growing conditions in the world.

New varieties are continuously evolved by the Sugarcane Breeding Institutes,
Agricultural Universities, and Sugarcane Research & Development Centres world over.
It would be therefore worthwhile for the growers to manipulate the environment in such
a way as to bring out the maximum expression of the yield potential possessed by
these varieties.

Classification of Sugarcane Varieties
Sugarcane is considered to be mature and ready for harvesting if it attains over 16%
sucrose and 85% purity of cane juice. The varieties, which attain such level at 12, 14
and 16 months age, if planted in December/January are broadly classified as early,
mid-late and late maturing types.

The terms early, mid and late are, therefore, not natural classfication and only
represent relative grading among varieties under comparative assessment. The main
idea of maturity-based classification of varieties is to facilitate harvesting of variety at
proper time in order to enhance over all recovery and consequently the sugar
production.

Proper Varietal Proportions
Proper proportion of area should be kept under early, mid-late and late maturing
varieties to ensure proper supply of cane of desired quality throughout the crushing
period. Proper varietal proportion will not only increase the total sugar recovery but will
also maintain it throughout the crushing season. a ration of 30:40:30 has been
suggested for early, mid-late and late ripening varieties for optimal performance and
utilization of the crushing seasons.

With in a maturity group, there should be more than one variety in the factory zone. It
is for simple reason of providing insurance against epidemic of pest or disease of the
crop, which may otherwise completely wipe out the crop.

Choice of Variety
Important considerations in choosing an appropriate variety include cane yield, juice
quality, age group, suitability to the growing conditions viz., soil type, irrigation regime,
season etc., ratooning potential, resistance to pests & diseases and adverse growing
conditions.
Some of the desirable varietal attributes one should look for are high yield potential,
high sucrose content, good field appearance, higher tillering capacity, medium thick to
thick and long stalks, long internodes, erect growing habit, non-lodging, non-flowering
or shy flowering, good ratooning ability, absence of spines on the leaf sheaths,
absence of splits on the stalks, less bud sprouting and resistance to prevailing local
problems.

33. 32
Varietal defects include lodging tendency, flowering propensity, disease susceptibility,
cavity development, high fibre content, big and bulged buds which may be damaged
during transportation, heavy spines on leaf sheath, drying of green top at maturity, tight
leaf clasping, presence of heavy pith, growth cracks or splits.
These defects may appear as minor and insignificant, at first, but they understandably
draw the growers attention when the varieties come into cultivation.
World over sugarcane cultivars receive a designation, which corresponds to the
country wherein they were developed/obtained. A few examples could be given:
Argentina - NA; South Africa - N; Australia - Q; Brazil - CB, IAC, PB, RB and SP;
Colombia - ICA; Cuba - C; USA - CP; Philippines - Phil; India - Co; Indonesia - POJ;
Peru - PCJ; Egypt - E; Puerto Rico - PR; and Mauritius - M. Three or more digits
usually follow the sigla. Improved varieties under cultivation in major sugarcane
countries are given in Table 6.

Table 6. Sugarcane: Improved Varieties Under Cultivation in Different Countries
SS..NNoo.. CCoouunnttrryy IImmpprroovveedd vvaarriieettiieess
11 BBrraazziill SSPP--7777--55118811,, RRBB--8855--55445533,, SSPP--8811--33225500,, SSPP--8800--11881166,,
RRBB--8855--55111133,, SSPP--8800--33228800,, RRBB--11004499,, SSSSSSPP--7711--55118811,,
BBRR8855--55111133,, BBRR7722--445544,, BBRR8833--55448866
22 IInnddiiaa CoS.687, CoPant.84211, CoJ.64, CoLk.8001,
Co.1148, CoS.767, CoS.802, CoC.671, CoC.85061,
Co.8021, Co.6304, Co.1148, CoJ.79, CoS.767,
Co.740, CoM.7125, Co.7527, CoC.671, Co.740,
Co.8014, Co.7804, Co.740, Co.8338, Co.6806,
Co.6304, Co.7527, Co.6907, Co.7805, Co.7219,
Co.7805, Co.8011
33 LLoouuiissiiaannaa CP 65-357, CP 70-321, CP 72-370, CP 74-383, CP
79-318, LCP 82-89, LHo 83-153, LCP 85-384, HoCP
85-845, LCP 86-454, HoCP 91-555
44 TThhaaiillaanndd 9911-- 22 --2299,, KK 9922 --118811,, KK 9955 --8844
55 CChhiinnaa
66 HHaawwaaiiii
77 SSoouutthh
AAffrriiccaa
CCPP 6666 -- 11004433,, NNCCoo 337766,, NN 1122,, NN 1144,, NN 1166,, NN 1177,, NN 1199,,
NN 2211,, NN 2222,, NN 2233,, NN 2244,, NN 2255,, NN 2266,, NN 2277,, NN 2288,, NN 2299,,
NN 3300,, NN 3311,, NN 3322,, NN 3333,, NN 3355,, NN 3366,, NN 3377,, NN 3399,, NN 4400,,
NN 4411


Land Preparation

For higher sugarcane yields, providing optimum soil environment is an essential pre-
requisite since the crop remains in the field for about 5 to 6 years due to the practice of
raising several ratoon crops.

34. 33

Good Land Preparation Improper Land Preparation

Further intense mechanization involving traffic of heavy machinery from planting to
harvesting and transporting to the sugar mill or distillery, can cause the deterioration of
soil physical conditions. This translates into soil compaction with a cohort of harmful
side effects viz., reduction in storage & movement of air and water, mechanical
difficulty for root growth and difficulty in absorption of nutrients from the soil itself and
from the fertilizer.

Therefore a through land preparation every time a new crop is planted is absolutely
essential to bring the soil to fine tilth for proper germination of the sets and field
emergence and root growth.

Tillage is the physical manipulation of the soil with appropriate implements to loosen
the surface soil layer.

Objectives of Land Preparation
• To prepare a seed bed which permits optimal soil water air relations
• Good physical conditions for early root penetration and proliferation
• To incorporate preceding crop residues and organic manures
• To destroy weeds and hibernating pest & disease organisms
• To facilitate proper soil chemical and microbial activity
Tillage operations through tractor drawn implements are most ideal and quick. For
initial ploughing use either mould board plough or disc plough. Whenever, soil turning
is desired, a mould board plough should be used.

On the other hand when the soil is hard, uneven and composed of crop stubbles, a
disc plough is preferable. Ploughing at optimum soil moisture content is very essential
to achieve tilth. Too wet soil interrupts movement of machinery and causes destruction
of soil structure.

35. 34
On the other hand too dry soil will not allow tynes to penetrate deep and results in
frequent mechanical breakdowns, increased power requirement and cloddy soil
surface affecting soil water air relations.


Without Subsoiling With Subsoiling

The secondary tillage operations are carried out using disc harrows, tyned harrows or
rotavator. The rotavator is a very useful multi purpose implement, which cuts the crop
residues, shred them and incorporates in the soil in one pass. Use mechanical
methods (subsoiling or chiseling or deep ploughing) or biological means (green
manuring between last ratoon harvest and start of a new crop) to destroy the
compacted layer and to allow roots to develop normally. Subsoiling was also shown to
reduce fuel consumption, working time and facilitate optimum plant population.

Steps in Land Preparation Involve the Following:
• Subsoiling or chiseling to a depth of 50 to 75 cm to break hard compact sub-pan
layer
• Ploughing to incorporate previous crop's crop residues and organic manures
• Discing to break clods
• Land shaping to provide the required gradient for draining excess water during
rainy season
• Field layout - Construct ridges & furrows and shape them. Depth of furrows
should be 25 cm. The furrow bottom should be loosened to about 10 cm.
• Provide drainage channels, which are deeper than the furrows along the field
borders as well as within the field at regular intervals. Drainage channels are
particularly important in the high rainfall areas to drain the excess water during
rainy season.
• Table 7 summarizes the power requirement and output during land preparation.

36. 35
Table 7. Sugarcane: Power Requirement and Work Ouput for Land Preparation

Power requirement/ha
Operation
kWatts
Diesel
(Litres/ha)
Output
(ha/hr)
PPrree--ddiisscciinngg 112255 1188 22..55
RRiippppiinngg 116655 4488 00..55
PPlloouugghhiinngg 116655 2244 11..77
PPoosstt--ddiisscciinngg 112255 1188 22..55
LLaanndd lleevveelliinngg 112255 77 33..55
RRiiddggiinngg 7700 1166 00..55


Planting Material

Sugarcane is vegetatively propagated for commercial cultivation. Different kinds of
planting materials viz., cane setts; settlings and bud chips are used for raising
sugarcane crop.

Cane Setts
Stem cuttings or sections of the stalks are called "setts" or seed pieces. Each sett
contains one or more buds. Always use fresh, genetically pure, pest and disease free
setts as seed material. Generally, three bud setts are used for planting throughout the
world, while in some areas two-bud setts are also used.

Three Bud Sett (Source: Verma, 2004)

Experimental evidence shows that germination percentage of 3-bud setts is higher
than the setts having more or less than 3-buds. The middle bud of a 3-bud sett has the
highest germinating capacity followed by top end bud and the bottom end bud,
respectively (Verma, 2004). The middle bud has an advantage in germination
because, as a non-terminal bud having nodes on either side, its moisture resources
are better protected than those of the terminal buds.

37. 36

Middle bud showing the highest germinating capacity in 3-Bud Sett
(Source: Verma, 2004)

Germination capacity of single-bud sett is very poor due to loss of moisture from cut
ends on either side. Further the plants arising from single-bud setts also lack vigour
and yield low as compared to those from three-budded setts. Thus the preference
given to three-budded setts over single-bud setts is partly based on germination
capacity and partly on initial vigour of the germinated plants and cane yield.

If whole cane stalk is planted without being cut into setts, usually few buds at its top
end germinate and the lower end buds remain inactive due to top dominance. The
effect of top dominance is eliminated when stalk is cut into pieces.

Settlings
Cane setts with roots and shoots are known as settlings. Settlings can be raised either
in nursery beds or in polythene bags. Single node settlings are used as a planting
material in spaced transplanting technique of raising sugarcane crop.


Single bud settling (Source: Verma, 2004)

Bud Chips
Little portion of stem with one bud is known as bud chip. Bud chips are used to raise
settlings in nursery. They were found to produce a good crop when transplanted in
main field. The principal advantage of bud chips is substantial saving in seed material.

38. 37
Seed requirement is reduced to less than one ton per ha. Adopting the following
procedure raises settlings from bud chips:
• Prepare the bud chips from whole cane using a sharp edged knife in such a way
that each bud has a little portion of stem
• Plant the bud chips on raised nursery beds adopting a inter-row spacing of 7.5
cm at the rate of 300 buds/m
2

• Alternatively nursery can be raised in polybags of 15 cm x 10 cm size
• Fill the polybags with homogeneous mixture of equal quantity of soil, sand and
well rotten compost
• Plant the bud chips in polybags with the bud facing upwards and cover with soil
mixture to avoid drying of the bud
• Bottom of the bags should have holes to facilitate drainage
• Ensure regular watering of bags or nursery area
• Settlings are ready in 5 - 8 weeks for transplanting in the main field
• Under good management conditions establishment of transplanted seedlings in
the main field is high (90-100%)
Raising of Seed Cane Crop
The normal practice in many parts of the world is to
use commercial crop of sugarcane for seed purposes.
Characteristics for good seed are seldom taken into
consideration. Many growers do not care for seed
quality and many of those who do, select the seed only
at the sett cutting and planting stage. This is not
enough. If a grower wants to be sure of getting good
and disease free seed cane he should raise the seed
crop separately. This crop should be kept completely
free from pests and diseases by constant field scouting
from the very beginning.

Moreover, seed quality is not merely a matter of pest
and disease freedom. Seed has to be in high water
content and of good nutritional status. Neglect in
raising good seed crop is one of the major defects in
sugarcane cultivation all over the world. (In the picture above: Bud Chip)

Use of sugarcane seed from the commercial crop has been responsible for rapid
multiplication of a large number of diseases like red rot, wilt, smut, ratoon stunting and
grassy shoot which adversely affect the cane yield and quality. It is, therefore, raising
of healthy and vigorous sugarcane crops for seed purpose is essential and
recommended.

39. 38
• Select an upland field for raising seed crop with no soil problems (soil salinity,
acidity, waterlogging etc) and adequate irrigation facility
• Prepare the soil thoroughly and incorporate 20-25 tons/ha of FYM 15 days
before planting
• Provide field channels and field drains to prevent rain water traversing from
adjoining field to check spread of red rot disease
• Select seed material from previously raised seed nursery crop and prepare the
setts. Use only sterilized setts to avoid transmission of certain diseases like
RSD and GSD
• Give heat treatment (heat therapy) to eliminate seed borne diseases and
organomercurial treatment to protect the setts from soil borne diseases to
ensure better germination
• Adopt narrow spacing of 75 cm to obtain higher yield of setts per unit area
• Use 25% higher seed rate than normal cane crop
• Apply higher nutrient dose of 250 kg N + 75 kg P2O5 + 125 kg K2O/ha
• Irrigate the crop at optimum levels to avoid any water stress during crop life
taking in to account evaporative demand of the atmosphere (ET
o) and Crop
characteristics (K
c) at different crop growth stages
• Provide weed free environment for better growth of the crop and also to avoid
infestation of pests and diseases
• Adopt field scouting for timely control of pests and diseases
• Rouge out the affected clumps and plants of other varieties
• Protect the crop from lodging, binding and propping
• Crop is ready in 7 - 8 months. Setts obtained from such crop contain healthy
and sound buds, higher moisture content, adequate nutrients, higher amounts
of reducing sugars, therefore, establish quickly and grow vigorously thus
ensuring a good commercial main field crop.
Preparation of Setts for Main Field Planting
• Harvest the seed crop one day before planting to obtain higher percentage and
uniform germination.
• Prepare the setts always one day before planting by giving sett treatment.
• Planting material or seed cane should be free from aerial roots and splits.
• Avoid damage to buds while cutting setts.
• Change the seed material after every two to three seasons. In case if it is
inevitable to use mature cane as seed, the top one-third portion can be used
satisfactorily.
Ideal Seed Cane
• Always use seed cane obtained from a seed crop of 7-8 months
• Free from disease and pest infestation like red rot, wilt, smut, ratoon stunting
disease etc
• Possesses healthy buds without any damage in handling and transport.

40. 39
• Buds with higher moisture content, adequate nutrients, higher amount of
reducing sugars and viability.
• Free from aerial roots and splits.
• Pure in quality.
Seed Cane Treatment
• Objective: To protect the
crop from soil borne
diseases causing
pathogens, which usually
gain entry into the setts
through the cut ends
following planting and
cause sett rotting and
damage to buds, thus
affecting germination.
• Most farmers don't treat the
setts before planting which
results low plant population
per unit area consequently
reducing the yield

In the Pictures above: Sett treatment with fungicide against soil borne pathogens + moist hot
air treatment of setts against seed borne diseases
In the picture below: Termite damaged setts (Source: Verma, 2004)

41. 40
• Treat the setts soon after cutting in 0.1% (at 1g/liter) Carbendazim solution for
15 minutes.
• Three important diseases viz., grassy shoot disease, smut and ratoon stunting
disease are carried forward through seed cane material. These diseases lead to
progressive decline in yields and degenerate sugarcane varieties. For control of
these diseases treat the seed material (setts) with moist hot air at 52°c for 30
minutes.
• To control termites early shoot borer and scale insects treat the setts in a
systematic insecticide viz. Malathion 50EC (at 2 ml/liter) or Dimethoate 30EC (at
3 ml/liter) for 15 minutes.
Seed Rate
Under drip irrigated paired-row
system of planting [(0.6m +
1.20m) x 0.12m], about 60,000
two-bud or 40,000 three-bud
treated setts would be required
to plant one ha of land. With
proper germination of buds,
this seed rate is adequate to
give a gapless stand and raise
a successful crop.

Nearly 10-12 tons of seed
cane is required to plant one ha of field. However, it is better always to go by number
of setts per ha rather than weight basis as sett weight in sugarcane varies largely with
varieties.

Measures to obtain higher germination
Some important yet simple measures to obtain higher uniform plant population are as
follows:
• Using quality setts as
seed material obtained
from a short seed crop
devoid of any primary
infection
• Using preferably two
eye bud setts instead of
three bud setts as seed
material
• Careful preparation of
setts without damaging
the buds or setts

42. 41
• Using sterilized knives for preparing setts to avoid transmission of root stunting
and grassy shoot diseases
• Planting freshly prepared and treated setts
• Giving adequate and frequent irrigation's during germination phase
• Control of weeds through pre-emergence herbicides
• Seed treatment with fungicide and pesticides
Transplanting Technique

Seedlings are raised in a nursery bed using single bud setts. When the seedlings are
of about 6 week old, they are transplanted in the prepared main field.

In the pictures on the right and below (Source: Verma, 2004):
• Single bud sett nursery
• Single bud sett settlings from nursery for transplanting in main field
• Transplanting In main field

Advantages
• Saving in the seed cost as the seed requirement is only about 2-3 tons/ha
against the normal seed requirement of 10-12 tons/ha.

43. 42
• Synchronous
tillering leading
to uniform growth
and maturity of
stalk population,
which usually
gives better yield
and sugar
recovery.
• Sufficient time for
main field
preparation
• Saving in water
and fertilizer
• Better weed management

Planting Time

Sugarcane is grown under diverse agro-climatic conditions in the world. Therefore
there is a considerable variation in the planting dates. The optimum planting periods in
different countries are presented in Table 8.

Table 8. Recommended Planting Time in Different Countries
SS..NNoo.. CCoouunnttrryy SSeeaassoonn PPllaannttiinngg ttiimmee
Central-South May to October 11 BBrraazziill
NNoorrtthheeaasstteerrnn September to March
Tropical October to March 22 IInnddiiaa
SSuubbttrrooppiiccaall September to April
33 CChhiinnaa ------ November to April
HHaawwaaiiii Year round 44 UUSSAA
Southeastern August to March
55 MMeexxiiccoo ------ November to June
66 SSoouutthh AAffrriiccaa ------ May to November
77 AAuussttrraalliiaa ------ June to December
77 AArrggeennttiinnaa ------ May to November
88 CCuubbaa ------ November to May
99 TThhaaiillaanndd ------ June to July and November
1100 PPhhiilliippppiinneess ------ October to May
1111 PPaakkiissttaann ------ February to March

44. 43
Machinery Planting
Due to increase in labour scarcity use of cane planting machinery is on the rise in
different countries not only to achieve efficiency in planting operation but also to save
fuel expenses and time to cover large areas. Several types of planting machinery have
been developed in different countries to suit the local conditions.

Research on depth of soil cover over seed cane indicates that soil cover in excess of
four inches can cause yield losses. Growers should use a covering tool that will cover
the cane without pushing the cane closer than the width it was planted. Packing of
rows should be done immediately after covering.



In the picture: Planted Cane and Sett Coverage Using Machine

Germination Irrigation

To get uniform and higher germination
(sprouting) percentage of planted setts is quite a
technique in drip irrigated cane production. This
operation demands full attention of the farmer.

In the picture: Subsurface dripline laying
machine

In the following paragraphs we explain the
procedure to be adopted to get best results:

• Prepare the main field to fine tilth

45. 44
• Lay the drip laterals (driplines) at 15 to 20 cm depth using SDI laying machine
and test for their design performance. Under surface drip driplines are spread
on the soil surface.
• Plant the treated two or three budded setts at 10-15 cm depth by planting
machine adopting recommended planting pattern and spacing.

Surface drip Subsurface drip
• After ensuring proper coverage of setts start the irrigation. Continue irrigation
until a uniform wet band (not standing water) is formed along the dripline to a
depth of not less than 30 to 40 cm.
• Depending upon the soil texture and soil tilth achieved during land preparation it
would take about four to six hours.
• Examine the soil frequently at various places in the planting zone i.e, 10 to 15
cm of soil depth, for ascertaining the moisture status. As the days pass on soil
moisture content decreases.
• Depending upon the soil texture and the climatic conditions (i.e, evaporative
demand of the atmosphere), in about 3 to 5 days the soil moisture content in the
planting zone will deplete to a level not congenial for germination process of the
cane. When this happens start the second round of irrigation in time so that the
bud sprouting process is not interrupted. Continue the second irrigation
operation similar to the first round i.e., until uniform wet moisture band is
achieved. But this time the irrigation duration will be less may be 50% of the first
irrigation cycle (i.e., 2 to 3 hours) to achieve the same level of moisture status
and wetting pattern in the soil. However, this needs to be confirmed before
terminating the irrigation.
• Normally after 3 to 4 such irrigation cycles an experienced grower can obtain a
very high germination percentage and uniformity of growth by adopting the
above-described method.

46. 45
• Poor soil conditions and improper land preparation affect but sprouting,
germination and crop emergence.


In the pictures above:
• Germination irrigation in surface drip to achieve a wetted strip
• Uniform emergence of sugarcane under drip irrigation

Weed Management

In sugarcane weeds have been estimated to cause 12 to 72 % reduction in cane yield
depending upon the severity of infestation.

The nature of weed problem in sugarcane cultivation is quite different from other field
crops because of the following reasons
• Sugarcane is planted with a relatively wider row spacing
• The sugarcane growth is very slow in the initial stages. It takes about 30 - 45
days to complete germination and another 60-75 days for developing full
canopy cover
• The crop is grown under abundant water and nutrient supply conditions
• In ratoon crop very little preparatory tillage is taken up hence weeds that have
established in the plant crop tend to flourish well
Major weed flora observed in sugarcane fields are: Sedges- Cyprus rotundus;
Grasses-Cynodon dactylon, Sorghum helepense, Panicum spp, Dactylocternium
aegyptium, Broad leaved weeds - Chenapodium album, Convolvulus arvensis L.,
Amaranthus viridis L., Portulaca oleraceae L., Commelina bengalensis L., Trianthema
portulacastrum L.

Weeds flora in sugarcane field besides competing for moisture and light also remove
about 4 times N and P and 2.5 times of K as compared to crop during the first 50-days

47. 46
period. Weeds also harbour certain diseases and pests that attack sugarcane and thus
lead to indirect losses.

Doob grass (Cynodon dactylon), the cogan grass (Imperata cylindrica) are known to
play as alternate hosts to ratoon stunting disease of sugarcane. Thus weeds
essentially harm young sugarcane sprouts by depriving them of moisture, nutrients and
sunlight. Poor growth of cane resulting from weed infestation also affects quality.

Weeds that are present in the furrows i.e., along the cane rows cause more harm than
those present in the inter-row spaces during early crop growth sub-periods. Thus the
initial 90-120 days period of crop growth is considered as most critical period of weed
competition. Therefore the weed management practice adopted should ensure a
weed-free field condition for the first 3-4 months period.



In the picture:
Weed control through herbicides pays in sugarcane (Source: Verma, 2004)

Recommended Herbicides
A chemical program for weed control can help Louisiana growers produce maximum
yields of sugarcane when combined with sound agronomic practices such as timely
cultivation, selection of adapted varieties, proper fertilization, and disease and insect
control. Herbicides are expensive, and, unless applied properly and at the correct time,
they will not provide maximum control of weeds.

Spray equipment should be in good condition, properly calibrated (several times during
a season) and should have vigorous agitation capability (especially important for
wettable powders). Herbicides also should be accurately measured or weighed.

48. 47
Herbicides to control weeds are essential to prevent weed competition and losses in
sugarcane production. Sugarcane is most susceptible to weed competition during the
first eight to 10 weeks after cane emergence. Unless herbicides are applied
immediately after planting, weed seed present in the soil following a fallow program will
germinate, producing viable seeds and/or rhizomes.

As a result weeds can quickly re-infest a field, with the benefits of weed control in the
fallow period rapidly lost.
Selection of pre-emergence herbicides should be based on soil texture and organic
matter content, weed problem and the variety of sugarcane. For best results, apply
pre-emergence herbicides im mediately after planting

Recommendations for use of herbicides for weed control in sugarcane are summarized
in the table below:

Table 9. Pre and Post-Emergence Herbicides For Weed Control in Sugarcane

Dosage (kg/ha) based on clay%
S.No. Herbicide
Control
(weeks)< 20% 21 - 30% >30%
PPrree--EEmmeerrggeennccee
1 AAttrraazziinnee 5500 FFWW 6- 8 2.0 2.5 3.0
2 AAmmeettrryynn 8800 WWPP 6- 8 2.0 2.5 3.0
3 DDiiuurroonn 8800 WWPP 5-7 2.0 2.0 2.5
4 MMeettrriibbuuzziinn 7700 WWPP 10-12 2.0 2.5 3.0
5 AAllaacchhlloorr 4488 EECC 6- 8 3.0 3.0 4.0
6 TTrriifflluurraalliinn 4488 EECC 5- 7 1.5 1.5 1.5
7 PPeennddiimmeetthhaalliinn 5500 EECC 8-10 1.5 1.5 1.5
8 TTeerrbbaacciill --- 1.0 1.2 1.5
9 DDiiuurroonn ++ 22,, 44--DD --- 1.2 + 1.8 1.2 + 1.8 1.2 + 1.8
10 AAttrraazziinnee ++ DDaallaappaann --- 1.25 + 2.5 1.25 + 2.5 1.25 + 2.5
PPoosstt -- EEmmeerrggeennccee
1 22,, 44--DD SSooddiiuumm ssaalltt 8800 WWSSPP 5-6 1.0 1.2 1.5
2 PPaarraaqquuaatt --- 2.0 3.0 4.0
3 GGllyypphhoossaattee 4411 WWSSCC 8 1.2 1.5 2.0
4 MMAAMMAA

Irrigation Water Management
Sugarcane being a long duration crop producing huge amounts of biomass is classed
among those plants having a high water requirement and yet it is drought tolerant. It is
mostly grown as an irrigated crop. The plant crop season being 12-18 months in India,
13-14 months in Iran, 16 months in Mauritius, 13-19 months in Jamaica, 15 months in
Queensland (Australia) and 20 - 24 months in Hawaii.

49. 48
Moisture Extraction Pattern
Most root biomass for sugarcane is found close to the surface and then declines
approximately exponentially with depth. Typically, approximately 50% of root biomass
occurs in the top 20 cm of soil and 85% in the top 60 cm. The percentage of roots in
the 0-30 cm horizon was 48-68%; from 30 to 60 cm, 16 - 18%; 60 to 90 cm, 3-12%; 90
to 120cm, 4-7%; 120 to 150 cm, 1-7%; and 150 to 180 cm, 0-4%. Thus the moisture
extraction pattern from different soil layers follows the root biomass distribution.

Root growth responds strongly to the soil environment, creating plasticity in the form
and size of the root system. The size and distribution of the root system is strongly
affected by the distribution and availability of soil water, causing differences in the
capacity of crops to exploit deeper soil reserves.

Root distribution of sugarcane crop raised on loamy soil irrigated at 7, 14 and 21 days
interval. Roots of a 12-month old plant crop were more deeply distributed under less
frequent irrigation presumably in response to drying of the surface. Deeper rooting
reduces the vulnerability of crops to soil water deficits by providing increased capacity
for uptake of deep reserves of soil water. It also aids in reducing lodging. Hence, drip
irrigated cane should be scheduled irrigations at less frequency during the initial 2 to 3
months period to promote deeper rooting. (In the graph above: Distribution of root
riomass with depth for sugarcane irrigated at frequencies of 7 days, 14 days and 21
days (Baran et. al., 1974)

Nutrient supply has also been shown to similarly affect the rooting patterns. High soil
strength causes slower root growth with reduced branching and thickened roots. High
water markedly affects root distribution, with a majority of studies showing that rooting
ceases within approximately 0.1 m of static water tables.

Restricted root growth above shallow water tables does not necessarily reduce crop
growth, as capillary rise can supply the crop with water and instances of water uptake
from within the saturated zone have been observed.

50. 49
A risk of water stress does result from the lack of root penetration in soils with high
water tables if ground water height falls rapidly, leaving the root system restricted to
dry soil.

Physiological Characteristics to be Considered for Efficient Water Managment
• A liberal water supply reduces the cane yield and/or sugar yield, while mild
water stress enhances the yield
• Excessive watering at tillering should be avoided since it coincides with active
root development and hinders nutrient uptake due to poor O2 diffusion
• Length of the cane determines the sink available for sugar storage since there is
no secondary thickening of the stem in sugarcane
• A drying off or cut out period of 4-6 weeks prior to harvest ensures an optimum
sugar yield
• Reduction of water during the ripeness to flower stage helps to control flowering
or arrows
Field Irrigation Schedule
The goal of an efficient irrigation scheduling programme is to "provide knowledge on
correct time and optimum quantity of water application to optimize crop yields with
maximum water use efficiency and at the same time ensure minimum damage to the
soil". Thus,
• Irrigation scheduling is the decision of when and how much water to apply to a
cropped field.
• Its purpose is to maximize irrigation efficiencies by applying the exact amount of
water needed to replenish the soil moisture to the desired level.
• Make efficient use of water and energy.
Therefore, irrigation scheduling for sugarcane involves precise estimation of depth of
water to apply at each irrigation, and the interval between irrigation, for each soil-plant-
climatic condition. With drip irrigation, intervals of irrigation are usually daily
irrespective of the evaporative demand of the atmosphere.

The crop evapotranspiration under standard conditions, denoted as ETc, is the
evapotranspiration from disease free, well-fertilized sugarcane crop, grown in large
fields, under optimum soil water conditions, and achieving full production under the
given climatic condition. The amount of water required to compensate the
evapotranspiration loss from the cropped field is defined as crop water requirement.

Although the values for crop evapotranspiration and crop water requirement are
identical, crop water requirement refers to the amount of water that needs to be
supplied, while crop evapotranspiration refers to the amount of water that is lost in
evaporation + transpiration.

51. 50

The irrigation water basically represents the difference between the crop water
requirement and effective precipitation. The irrigation water requirement also includes
additional water for leaching of salts and to compensate for non-uniformity of water
application.

Adequate soil moisture throughout the crop-growing season is important for obtaining
maximum yields because vegetative growth including cane growth is directly
proportional to the water transpired. Depending on the agro-ecological conditions,
cultivation practices adopted and crop cycle (12-24 months) seasonal water
requirements of sugarcane are about 1300mm to 2500mm distributed throughout the
growing season (Table 10). The amounts of water required to produce 1.0-kg cane, dry
matter and sugar are 50 - 60, 135-150 and 1000-2000g, respectively. The transpiration
coefficient of sugarcane is around 400. This means 400 m
3
of water is required to
produce one ton of dry matter.

Table 10. Sugarcane Water Requirements in Various Countries

SS..NNoo.. CCoouunnttrryy WWaatteerr rreeqquuiirreemmeenntt ((mmmm))
11.. AAuussttrraalliiaa 11552222 ((DDrriipp))
22.. BBuurruunnddii,, CCeennttrraall AAffrriiccaa 11332277 ttoo 22001177 ((FFuurrrrooww))
33.. CCuubbaa 11668811 ttoo 22113333 ((PPllaanntt))
44.. HHaawwaaiiii 22000000 ttoo 22440000 ((2244 mmoonntthhss))
55 JJaammaaiiccaa 11338877
66 MMaauurriittiiuuss 11667700 ((DDrriipp))
77 PPhhiilliippppiinneess 22445511 ((FFuurrrrooww))
88 PPoonnggaallaa,, SSoouutthh AAffrriiccaa 11555555
99 PPuueerrttoo RRiiccoo 11775522
1100 SSoouutthh AAffrriiccaa 11667700
1111 SSuubbttrrooppiiccaall IInnddiiaa 11880000 ((FFuurrrrooww))
1122 TTaaiiwwaann 11550000 ttoo 22220000 ((FFuurrrrooww))
1133 TTrrooppiiccaall IInnddiiaa 22000000 ttoo 22440000 ((FFuurrrrooww))
1144 VVeenneezzuueellaa 22442200 ((FFuurrrrooww))
1155 TThhaaiillaanndd 22660000 ((FFuurrrrooww))
SSoouurrccee:: SSeevveerraall

The Calculation Procedure for Crop Evapotranspiration, ETc, Consists of:

Calculation of Reference Crop Evapotranspiration (ET
o)
Collect available climatic data; based on meteorological data available, select
prediction method viz., either Penman-Monteith or Pan evaporation method to

52. 51
calculate ETo. Compute for necessary periods considering the growth subperiods of
the crop in question.

Construction of Crop Coefficient (K
c) Curve
Determine time of planting, identify the crop growth subperiods, determining their
lengths; Select Kc for a given crop growth sub-period under prevailing climatic
conditions. Construct the crop coefficient curve (allowing one to determine Kc values
for any period during the growing period); and


Calculation of ETc under standard conditions as a product of ETo and Kc.

The reference crop evapotranspiration (ET
o) estimated based on Penman-Monteith or
Adjusted USWB Class A Pan evaporation method reflects the evaporative demand of
the atmosphere for the location in question.



In the picture: USWB Class a Pan Evaporimeter for Estimating ET
o

While the crop factor (a dimensionless ratio) reflects the crop characteristics and
indicates the combined loss of water from a sugarcane field both by transpiration and
soil evaporation (Crop ET
c) relative to ETo over the same period.

Several workers have worked out estimates of crop factors experimentally for different
crop growth stages of sugarcane. The daily requirement in millimeters is converted to
the equivalent volumetric quantity for the area under drip (1 mm = 10 m
3
/ha).

A field irrigation schedule prepared based on above approach for irrigating sugarcane
grown in Tropical region of India is presented in the picture for field application.

53. 52

While the water requirement during different crop-growth subperiods and cumulative
ETc is depicted in the picture here. Such type of irrigation scheduling programmes can
be prepared for each location (depending up on the climatic data availability) in real
time operation.



Water Supply and Cane Yield
Frequency and depth of irrigation should vary with growth periods of the cane. The
relationship between relative yield decrease (1 - Ya/Ym) and relative
evapotranspiration deficit for the individual growth sub-periods is shown in the picture.
During the initial germination, field emergence and establishment of young seedlings
the crop requires less water, hence light and frequent irrigation water applications are
preferred.

54. 53
The water supply must be just sufficient to keep the soil moist with adequate aeration.
If the soil is allowed due to infrequent and less water application, the germinating buds
get desiccated leading to a lower and delayed germination.


On the other hand over irrigation leads to bud rotting due to lack of aeration, fungal
attack and soil reducing soil temperature. Thus both under and over irrigation are
detrimental for germination, resulting in low stalk population per unit area.

During the early vegetative period (formative) the tillering is in direct proportion to the
water application. An early flush of tillers is ideal because this furnishes shoots of
approximately same age. Any water shortage during tillering phase would reduce tiller
production; increase tiller mortality and ultimately the stalk population-an important
yield component.

55. 54
However, excess irrigation during tillering phase is harmful particularly in heavy soils,
since it coincides with active root development, which may be hampered by anaerobic
condition created in the soil as a result of over irrigation.

The yield formation or grand growth period is the most critical period for moisture
supply in sugarcane. This is because the actual cane yield build-up or stalk growth
takes place in this period. The production and elongation of inter-nodes, leaf
production on the stalk and its expansion, girth improvement, ultimately the stalk
weight takes place in this period. It is also the period for production of sugar storage
tissues. Therefore, crop reaches its peak water requirement in this stage. With
adequate water supply to maintain a sheath moisture content of 84-85% in the leaf
sheaths, 3,4,5 and 6 from the top during this period of active growth produces longest
inter-nodes with more girth (thick cane) and the total cane weight is greater.

On the other hand water deficits in yield formation period reduce stalk elongation rate
due to shortening of inter-nodes resulting in less cane weight and the effect is well
marked on yield at harvest. A severe water deficit during the later part of the grand
growth period forces the crop to ripen. In many an areas in India the tillering/early yield
formation period coincides with hot weather period (March - June).

The evaporative demand of the atmosphere is very high during hot weather period vis-
à -vis the crop water needs. Therefore management of available water supplies to
meet the peak water requirement is very crucial to realize optimum yield potential.

In ripening period the a restricted water supply or mild water deficits (sheath moisture
content of 74-76%) is necessary to bring the crop to maturity by reducing the rate of
vegetative growth, dehydrating the cane and forcing the conversion of total sugars to
recoverable sucrose. With the check of vegetative growth, the ratio between dry matter
stored as sucrose and that used for new growth increases.

On the other hand plentiful supply of water leads continued vegetative growth thus
affecting sugar accumulation process. However, when the plant is too seriously
deprived of water, it would disrupt the plant metabolism and loss of sugar content can
be greater than sugar formation. An important consideration is that soil should not be
allowed to crack, as it would cause root pruning and damage the root system.

When the crop is in the ripening period, a farmer may also have a just planted crop on
his farm in most situations. Therefore, the tendency of the farmer will be to provide
sufficient water to the new (young) crop and neglect the grown up crop that is to be
harvested. This situation is particularly true under limited water availability situations. If
the grown up crop is not irrigated as required it experiences severe water deficits and
there could be cane breakage, pith formation, significant reduction in cane weight,
increase in fibre content and deterioration in juice quality.

56. 55
The situation is further aggravated if the harvesting is delayed. Thus both the farmer
and the factory would suffer. Therefore, even for the grown up crop, reasonable
amount of water with restricted supply is necessary to obtain good cane yield.

Sheath Moisture Content
The sheath moisture or relative water content determined by crop logging technique is
presented in Fig. It has long been used to control water application to commercial
sugarcane crop, more particularly during ripening phase, when gradual increase in
water stress is used to stimulate sugar storage in the stem.

A ripening log is used to compare measured and desired sheath water content during
approximately 12 to 24 weeks (depending upon the crop duration) prior to harvest.

Sheath water content is measured on a periodic basis, and irrigation intervals and
amounts are varied to produce a gradual decline of sheath water content, from about
83% at the beginning of ripening to about 75% at harvest.



In the graphs / pictures above:
• Cane yield response to water deficits (Doorenbos and Kassam, 1979 )
• Optimum Sheath Moisture content indices for sugarcane (Lakshmikantham,
1983)
• Cane Yield Response to seasonal evapotranspiration [Thompson (1976) &
Jones (1980)]

In Hawaii and Taiwan sheath water content has been found to be a good indicator of
stem sugar content. Similar methods involving other tissues are in use in Mexico,
South Africa, India and Zimbabwe.

57. 56
Irrigation water is often limited and costly input. Therefore determination of optimum
amount of water over a crop period to achieve higher water use efficiency assumes
significance.

Several experiments conducted world over have indicated that the relationship
between cane yield and seasonal crop water use under a given climatic condition was
linear.

When irrigation plus rainfall is greater than the crop water requirement, anaerobic soil
conditions or N losses may reduce crop growth rates and cane yield.

Fertigation

Sugarcane being a giant crop producing huge quantity of biomass generally demands
higher amounts of nutrient elements. A large number of research experiments have
clearly demonstrated that for producing higher cane and sugar yields on a sustainable
basis application of adequate amounts of fertilizer nutrients viz., N, P and K is
essential.

At the same time the cost of chemical fertilizers have increased and there is a need to
improve fertilizer use efficiency for more benefits. The best answer to this challenge is
"Fertigation", where both water and fertilizers are delivered to crop simultaneously
through a drip irrigation system. Fertigation ensures that essential nutrients are
supplied precisely at the area of most intensive root activity according to the specific
requirements of sugarcane crop and type of soil resulting in higher cane yields and
sugar recovery.

Fertigation Offers Several Distinct Advantages in Comparison to Conventional
Application Methods:
• Distribution of plant nutrients more evenly throughout the wetted root zone
resulting in increased nutrient availability & uptake contributing to higher crop
growth rates and cane yields
• Supply of nutrients incrementally according to the crop developmental phases
throughout the season to meet the actual nutritional requirements of the crop
• Careful regulation and monitoring the supply of nutrients
• Application of nutrients to the soil when crop or soil conditions would otherwise
prohibit entry into the field with conventional equipment
• Minimal nutrient losses through consumption by weeds, leaching and runoff
• No damage to the crop by root pruning, breakage of leaves, or bending of
leaves, as occurs with conventional fertilizer application methods/equipment
• Less energy is expended in application of the fertilizer

58. 57
• Usually less labour & equipment are required for application of the fertilizer and
to supervise the application
• Soil compaction is avoided because heavy equipment never enters the field
• No salt injury to foliage
• Allows raising of crop on marginal lands, where accurate control of water and
nutrient ion in the plant's root environment is critical
Nutrient Uptake by Sugarcane


Absorption of macronutrients by the variety CB41 - 76 (Malavolta, 1982)

Fig. shows the accumulation of macronutrients by the variety CB 41-76 under Brazilian
conditions. Several works have indicated that there is a close relationship between
increase in stalk production and accumulation of N and K, which suggests that these
two elements "go together" in the nutrition and fertilization of the sugarcane plant. The
maximum rate of uptake of macronutrients by plant cane and first ratoon in the period
of higher growth rate is given in
Table 11.

59. 58
Table 11. Maximum Rate of Uptake of Nutrients by Plant Cane and Ratoon Cane
(Malavolta, 1994)

Element Plant cane Firfst ratoon
kg ha
-1
day
-1

Nitrogen 0.59 0.73
Phosphorus 0.08 0.11
Potassium 0.71 0.95
Calcium 0.45 0.33
Magnesium 0.24 0.26
Sulphur 0.16 0.31

Generally speaking, the content of the macro and micronutrients in the plant obeys the
following decreasing order:

K»gt; N»gt; P»gt;Ca»gt;S»gt;Mg»gt;Cl»gt;Fe»gt;Zn»gt;Mn»gt;Cu»gt;B»gt;Mo

Further most of the published data on the mineral requirements of sugarcane refer only
to the above ground parts, which are stalks and leaves. Table 12 is an attempt to show
the quantities of macro and micronutrients contained in the entire plant cane.

Table 12. Quantity of Macro and Micronutrients in the Below Ground and Aerial
Parts of Plant Cane
Roots Millable stalks Leaves Total
Element
Kg/ha
Nitrogen 8 83 77 168
Phosphorus 1 15 8 24
Potassium 4 109 105 218
Calcium 2 30 45 77
Magnesium 1 29 18 48
Sulphur 2 25 22 49
Chlorides -- -- 1 1
Silicon -- 98 150 248

g/ha
Boron 34 214 144 392
Copper 13 201 105 711
Iron 4900 3800 7900 16600
Mangnese 84 1170 1981 3235
Molybodynum -- 4 10 14
Zinc 72 437 336 845
Catani et al. (1959), Orlando Filho (1978), Haag et al. (1987),
Sampaio et al. (1987), Korndorfer (1989)

60. 59

Role of Nutrients

Nitrogen
1. N constitutes only a fraction of 1.0% of the total dry weight of mature cane
2. Key element influencing growth, yield & quality
3. Adequate and timely supply promotes - Tillering, Canopy development, Stalk
formation & stalk growth [internode formation, elongation, increase in girth &
weight
4. Root penetration and proliferation
5. Deficiency of N causes chlorosis, early leaf senescence, thinner & shorter stalk
and longer and thinner roots
6. Excess N prolongs vegetative growth, delays maturity and ripening; increases
reducing sugar content in juice and thus lowering juice purity, and increases
soluble N in juice affecting clarification; makes crop susceptible to lodging and
pest and disease attack

Phosphorus
1. Requirement is relatively less than N and K
2. Vital for plant metabolism and photosynthesis
3. Essential for cell division and thus indispensable for crop growth & development
4. Promotes tillering, canopy and stalk development
5. Promotes root penetration and proliferation
6. Adequate P [ 3-4mg/liter ] in cane juice is necessary for proper clarification
7. Phosphorus deficiency causes - Poor tillering & reduction in internodal length,
Delay in canopy closure and Reduction root surface area

Potassium
1. Required for several plant activities - Photosynthesis, carbon assimilation &
translocation of carbohydrates
2. Promotes sugar synthesis & its translocation to storage tissue
3. Imparts resistance against pests & disease attack and lodging
4. Regulates stomatal opening & closing and thus maintains turgor pressure under
unfavourable soil moisture conditions
5. Luxury consumption adversely affects the crystallization of sugar & higher sugar
losses in molasses
6. Deficiency of K affects growth by reducing internodal length, sugar synthesis
and recovery

61. 60

Causes of Nutrient Deficiency Symptoms
When a given nutrient is not present in the soil solution in a concentration sufficient for
normal growth and differentiation, visual symptoms of malnutrition may eventually
show up. The shortage of nutrients, which translate into symptoms of deficiency, could
be due to several causes as shown in Table 13. It is clear that the three chief causes
are low reserves to begin with, as it is the case of old weathered soils in the tropical
regions, decrease in availability, and absence or lack of the element in the fertilizer
programme at the rates it is applied.

Table 13. Main Causes of Deficiency Symptoms in the Sugarcane Plant
Element Cause
Any • Low soil reserve
• Absence or inadequate quantity in the fertilization or liming
programme
Nitrogen • Low organic matter content
• High acidity (lack of mineralization)
• High rainfall (leaching)
Phosphorus • High acidity and high sexquiooxides (fixation)
• Excess liming (lower availability)
Potassium • Excess liming (competition for uptake)
• High rainfall (sandy soils, leaching)
Calcium &
Magnesium
• Excess K in the fertilizer programme (competition)
Sulphur • See nitrogen
• Use of "concentrated" fertilizers
Boron • See nitrogen
• Excess nitrogen ("dilution" or inhibition in uptake)
• Excess liming (loss in availability)
Copper • Excess P in the fertilization programme(inhibition in
uptake)
• Excess liming (loss in availability)
Iron • High organic matter and moisture (loweravailability)
• Excess liming (loss in availability)
Manganese • High organic matter, Excess liming (loss in availability)
Molybdenum • High acidity (lower availability)
• Excess sulphate (inhibition in uptake)
Zinc • Excess liming (loss in availability)
• High P in fertilizer programme (inhibition uptake)
Source: Malavolta (1994)

Fertilizer recommendations in different states
Sugarcane being a heavy feeder requires very large quantities of nutrients for growth
and yield, accounting for 20 to 25% of the total cost of the production. The fertilizer
recommendations for sugarcane in different countries are given in Table 14.

62. 61
Table 14. Sugarcane: Recommended Nutrient Doses in Different Countries
NNNuuutttrrriiieeennntttsss (((kkkggg///hhhaaa)))
CCCooouuunnntttrrryyy CCCrrroooppp
NNN PPP2
22OOO5
55
KKK2
22000
RRReeemmmaaarrrkkksss
AAArrrgggeeennntttiiinnnaaa ------ 111000000 AAAdddaaapppttt tttooo rrreeeqqquuuiiirrreeemmmeeennnttt ------
AAAuuussstttrrraaallliiiaaa PPPlllaaannnttt cccaaannneee
RRRaaatttoooooonnn
555666
777888
222555---888000
------
777555---111555000
------
IIInnn aaaddddddiiitttiiiooonnn tttooo BBBuuurrreeeaaauuu
mmmiiixxxtttuuurrreee
BBBaaannnggglllaaadddeeessshhh ------ 111222000 888555 111111000 ------
BBBrrraaazzziiilll
NNNooorrrttthhh EEEaaasssttt
SSSooouuuttthhh EEEaaasssttt
CCCeeennntttrrraaalll WWWeeesssttt
SSSooouuuttthhh
PPPlllaaannnttt cccaaannneee
RRRaaatttoooooonnn
PPPlllaaannnttt cccaaannneee
RRRaaatttoooooonnn
PPPlllaaannnttt cccaaannneee
RRRaaatttoooooonnn
PPPlllaaannnttt cccaaannneee
RRRaaatttoooooonnn
666000---888000
666000---888000
555000---999000
555000--- 999000
333000---444000
444000--- 666000
444000---111000000
222000---444000
888000--- 111888000
222000---111000000
555000---111111000
222555---555000
333000---111222000
111555---666000
000---111222000
222000---666000
333000---111222000
444000---111444000
222000---111222000
111000---888000
333000---111222000
222000---999000
333000---111222000
000---666000
NNN --- 222///333 sssiiidddeee---dddrrreeesssssseeeddd
PPP &&& KKK aaaccccccooorrrdddiiinnnggg tttooo sssoooiiilll
aaannnaaalllyyysssiiisss
PPP &&& KKK aaaccccccooorrrdddiiinnnggg tttooo sssoooiiilll
aaannnaaalllyyysssiiisss
AAAsss aaabbbooovvveee
AAAsss aaabbbooovvveee
AAAsss aaabbbooovvveee
BBBrrriiitttiiissshhh GGGuuuyyyaaannnaaa ------ 666555---999000 555000---111000000 666000---111555000 ------
CCCooolllooommmbbbiiiaaa PPPlllaaannnttt cccaaannneee
RRRaaatttoooooonnn
555000---777000
555000---111000000
555000---111000000
666000---111222000
666000---111555000
666000---111555000
NNN --- SSSiiidddeee dddrrreeesssssseeeddd
aaaccccccooorrrdddiiinnnggg tttooo llleeeaaafff
aaannnaaalllyyysssiiisss
PPP &&& KKK rrraaattteeesss dddeeepppeeennndddiiinnnggg
uuupppooonnn sssoooiiilll aaannnaaalllyyysssiiisss
CCCooossstttaaa RRRiiicccaaa PPPlllaaannnttt cccaaannneee
RRRaaatttoooooonnn
888000---222000000
111000000---222555000
666000---222000000
555000---222000000
888000---222000000
888000---222555000
------
CCCuuubbbaaa PPPlllaaannnttt cccaaannneee
RRRaaatttoooooonnn
000
333555---111555000
000---555000
000---555000
000---111222000
000---111555000
PPP &&& KKK rrraaattteeesss dddeeepppeeennndddiiinnnggg
uuupppooonnn sssoooiiilll aaannnaaalllyyysssiiisss aaannnddd
yyyiiieeelllddd llleeevvveeelll
EEEcccuuuaaadddooorrr PPPlllaaannnttt cccaaannneee
RRRaaatttoooooonnn
111222000
999000
777555---111333555
------
777555---111999555
------
NNN---111///333 sssiiidddeee dddrrreeesssssseeeddd
PPP &&& KKK rrraaattteeesss aaaccccccooorrrdddiiinnnggg
tttooo sssoooiiilll aaannnaaalllyyysssiiisss
IIInnndddiiiaaa ------ SSSEEEEEE NNNEEEXXXTTT TTTAAABBBLLLEEE ------
IIInnndddooonnneeesssiiiaaa ------ 111222000 ------ ------ PPP &&& KKK rrraaattteeesss aaaccccccooorrrdddiiinnnggg
tttooo sssoooiiilll aaannnaaalllyyysssiiisss
JJJaaammmaaaiiicccaaa ------ 888000---111666000 ------ ------ PPP &&& KKK rrraaattteeesss aaaccccccooorrrdddiiinnnggg
tttooo sssoooiiilll aaannnaaalllyyysssiiisss
MMMaaauuurrriiitttiiiuuusss ------ 111000000---111222555 ------ ------ 222 --- 111 ---111 mmmiiixxxtttuuurrreee
MMMeeexxxiiicccooo ------ 111222000---111888000 000---111555000 000---111555000 MMMooosssttt fffrrreeeqqquuueeennnttt rrraaattteeesss:::
111222000 NNN+++666000 PPP 2
22OOO5
55+++666000
KKK2
22OOO
PPPaaakkkiiissstttaaannn ------ 999000---111666000 ------ ------ ------
PPPhhhiiillliiippppppiiinnneeesss
VVVMMMCCC DDDiiissstttrrriiicccttt
LLLuuuzzzooonnn
PPPuuueeerrrtttooo RRRiiicccooo
------ 111222555
111222000---111444000
111333555---222000000
111222000
------
666222
111888000
------
111111222
------
SSSooouuuttthhh AAAfffrrriiicccaaa
CCCoooaaassstttaaalll
LLLooowwwlllaaannnddd
NNNaaatttaaalll MMMiiidddlllaaannnddd
LLLooowwwvvveeelllddd
PPPlllaaannnttt cccaaannneee
RRRaaatttoooooonnn
PPPlllaaannnttt cccaaannneee
RRRaaatttoooooonnn
PPPlllaaannnttt cccaaannneee
RRRaaatttoooooonnn
111000000---111222000
111444000
888000
111222000
111222000
111000000
444000
222000
666000
444000
333000
111000
111000000
111555000
111222555
111777555
111222555
111777555
NNN aaannnddd KKK 2
22OOO fffooorrr ppplllaaannnttt
cccaaannneee iiinnn 222 ssspppllliiittt
aaappppppllliiicccaaatttiiiooonnnsss
HHHaaawwwaaaiiiiii (((UUUSSSAAA)))
IIIrrrrrriiigggaaattteeeddd
RRRaaaiiinnnfffeeeddd
PPPlllaaannnttt cccaaannneee
PPPlllaaannnttt cccaaannneee
444000000
333000000
222888000
222888000
444000000---444555000
444000000---444555000
NNN iiinnn 222 ssspppllliiittt aaappppppllliiicccaaatttiiiooonnnsss

63. 62
Leaf Analysis
Leaf analysis may be considered a method, which evaluates the soil supply of
available elements using the plant itself as an extracting agent. A general
representation of the relationship between leaf concentration and cane yield is
presented in fig.


Relationship Between Leaf Concentration and Cane Yield
(Prevot & Ollagnier, 1956)

The picture describes several situations, which may occur. Clockwise the following
segments are shown:
• Curve in "C" - Yield is increased but leaf level is reduced; this happens when
the rate of dry matter production is higher than the velocity of uptake or
transport of the element into the leaf tissue which causes its dilution
• Zone Of Deficiency Or Adjustment - Only in this section is the relationship
between leaf level and growth or yield is observed, and very often there is a
linear relationship between increase in leaf concentration and yield;
• Lower Critical Level - Usually a narrow band below which yield is reduced due
to a shortage of the element
• Zone Of Luxury Consumption - It is wider in the case of macronutrients like K,
and much shorter in other cases such as that of B; leaf level increases wheras
production remains constant, there is therefore, a waste of fertility or fertilizer;
• Upper critical level - A zone which separates the yield plateau from the toxicity
zone;
• Zone of toxicity - Leaf content increases even further and yield drops, either as
consequence of a toxic effect of the element, or as a result of unbalance among

64. 63
In the agricultural practice, the goal is not the maximum physical production but rather
the realization of the maximum economic yield (MEY). For this reason the concept of
critical level or lower critical level was redefined with the introduction of an economical
component: it is the range of an element in the leaf below which production is
restricted and above which fertilizer application is no longer economical.

This means that above this physiological-economical critical level, both yield and leaf
content of the element could rise in response to the fertilization. The increase in yield,
however, does not pay the additional fertilizer and the cost of its transport and
distribution. Thus levels of nutrients considered adequate for economic yield are
presented in Table 15 & 16.

Table 15. Levels of Macronutrients Considered Adequate for Maximum
Economic Yield
%% ooff ddrryy mmaatttteerr
CCoouunnttrryy CCrroopp
NN PP KK CCaa MMgg SS
PPllaanntt 11..9900--22..550000..2211--00..330011..3300--22..000000..2200--00..6600 00..1100--00..3300 ---- AAuussttrraalliiaa
RRaattoooonn 11..9900--22..550000..2211--00..330011..3300--22..0000 ---- ---- ----
PPllaanntt 11..9900--22..110000..2200--00..224411..1100--11..330000..8800--11..0000 00..2200--00..3300 00..2255--00..3300BBrraazziill
RRaattoooonn 22..0000--22..220000..1188--00..220011..3300--11..550000..5500--00..7700 00..2200--00..2255 00..0088--00..3355
PPllaanntt 22..11 00..2211--00..335511..2255--22..000000..1155--00..2200 00..1122--00..1188 00..0088--00..3355BBrriittiisshh GGuuyyaannaa
RRaattoooonn 11..99 00..2211--00..335511..2255--22..000000..2200--00..2244 00..1122--00..1188 ----
CCoolloommbbiiaa ---- 11..8800--22..000000..2255--00..335511..6600--11..8800&&ggtt;; 00..2255 &&ggtt;; 00..2200 ----
IInnddiiaa ---- 11..9966 00..008866 11..9999 ---- ---- ----
PPuueerrttoo RRiiccoo ---- 11..6600--22..000000..1188--00..224411..5555--22..0000 ---- ---- 00..1133
SSoouutthh AAffrriiccaa ---- 11..7700--11..990000..1100--00..220011..0055--11..110000..1155--00..1188 00..0088 00..1122--00..1133
UUSSAA ---- 11..5500--11..775500..1188--00..222211..2255--11..775500..2288--00..4477 00..1144--00..3333 00..1133--00..1188
RReeuutteerr ((11998866)),, MMaallaavvoollttaa ((11998866)),, EEvveennss ((11996677)),, GGaarrcciiaa OOccaammppoo ((11999911)),, SSrriivvaassttaavvaa ((11999922)),,
SSaammuueellss ((11997711)),, GGoossnneellll && LLoonngg ((11997711)),, AAnnddeerrssoonn && BBoowweenn ((11999900))

Table 16. Levels of Macronutrients Considered Adequate for
Maximum Conomic Yield %% CCoouunnttrryy CCrroopp
BB CCll CCuu FFee MMnn MMoo SSii ZZnn
AAuussttrraalliiaa ---- ---- ---- 22 5500 ---- ---- ---- 1100
PPllaanntt 99--3300 ---- 88--1100 220000--550000110000--22550000..1155--
00..3300
---- 2255--5500BBrraazziill
RRaattoooonn 99--3300 ---- 88--1100 8800--1155005500--112255---- ---- 2255--3300
BBrriittiisshh
GGuuyyaannaa
---- 22--1100 ssmmaalllleerr
tthhaann 00..55%%
55--110000 44--1155 2200--22000000..0088--11..00 ---- 1155--5500

65. 64
SSoouutthh AAffrriiccaa ---- 11..66--1100 4499--99115533--1122 1155 ---- 1122--2255
UUSSAA ---- 33--88 00..006688%% 77--660000 2200--2211 1144--22335500..0055--44 11..55--44%%1199--3388
AAnnddeerrssoonn && BBoowweenn ((11999900)),, MMaallaavvoollttaa ((11998822)),, EEvveennss ((11996677)),, WWoooodd ((11998877)),,
SSccrrooeeddeerr eett..eell ((11998833)),, AAnnddeerrssoonn && BBoowweenn ((11999900))


Fertigation Programme
The aim of the fertigation programme is to cover the difference between requirement
and supply, that is:

(M) Fertilizer = [M (requirement - supply)] f

Wherein M = a macro or micronutrient, f = is a factor higher than 1 destined to
compensate for losses due to volatilization, leaching, fixation and immobilization.

Whenever the soil supply is lower than the crop requirement, fertilizers have to be
added in order to increase and to keep M (in soil solution) at a level compatible with
the plant needs. In order to make practical fertilizer recommendations, we have to
answer several questions, namely:

What? Which Element(s) is (are) Limiting Growth and Production; How Much?
What Quantity Has to be Added?
The capacity of the soil to supply nutrients can be evaluated through leaf analysis
already dealt with, and more frequently via soil chemical analysis. Further the cation
exchange capacity, clay content, efficiency factor etc have to be considered to quantify
the nutrient requirement.

When? In What Stages Fertilization is to be Done?
As shown in fig. accumulation pattern as a function of crop ontogeny has to be taken in
to account for timing of fertilizer application. Both nitrogen and potash fertilizers tend to
increase the osmotic pressure of the soil solution which when too high could damage
the seed cane or the roots. Nitrogen in mineral forms can be leached from the
rhizosphere. The same is true for K in the case of soils with low CEC. These facts
seem to point out the need to apply only part of the N requirement at planting and
doing the same for potash in sandy soils.

Nitrogen requirement of sugarcane is greatest during the tillering (formative) phase.
This is required for adequate tiller production and canopy development. Tillering in field
grown sugarcane commences around 30 to 45 days after planting. Therefore,
adequate N supply should be made available to the crop in the soil from the start of
tillering phase. Further, crop requirement for N is higher in early grand growth period.

66. 65
This facilitates cane formation; checks tiller mortality and promote cane growth.
Application of more N at later phase of active crop growth period not only promotes
late tiller formation, but also affects sugar recovery due to reduced juice sucrose (Pol)
percent, increase in soluble N in juice, water shoot formation besides attracting pests
and diseases.

Phosphorus need of sugarcane is greater in the formative phase of the crop. Thus, the
optimum time of P application is during initial stages of crop growth. Therefore,
sufficient P must be made available in the soil during formative phase for absorption by
the crop.

Potassium applications are usually done along with N application. This is because of
better utilization of N by the crop in the presence of K; therefore, potassium should be
applied along with N. However, late application of K at around six months has also
been found to improve sugar recovery.

In general all the phosphorus should be applied before 4 months, nitrogen before 6
months and potassium before 7 months period. Relative requirement of NPK (%) at
different crop growth stages is shown in Fig.


Relative requirement of NPK at different crop growth stages of sugarcane
(Bachchhav, 2005)

How? What is the Most Efficient Way of Fertilization?
The efficacy of fertilizer depends on several factors, such as: process of contact
between the element and the root, distribution of the root system, type of crop (plant
crop or ratoon) and spacing, type of fertilizer and application rate. Root interception,
mass flow and diffusion make the following percent contributions to the total of the
element, which reaches the root surface: N (1, 99 & 0), P (2, 4 & 94); K (2, 20 & 78).

67. 66
While in the case of nitrogen mass flow plays an almost exclusive role for the contact,
diffusion is the chief mechanism (94%) for P and for K (78%). It follows therefore that
as long as P is placed adequately, both N and K will be taken equally well. Thus from
the above it appears that fertigation is the best option of fertilization.

With what? Which fertilizers are to be Used?
Table 17 lists the main water soluble fertilizers used in the sugarcane world. It is
desirable to use water soluble specialty fertilizers in view of the following features:

Table 17. Fertilizers Suitable for Fertigation Via Drip Irrigation System

NNuuttrriieenntt WWaatteerr ssoolluubbllee ffeerrttiilliizzeerrss NNuuttrriieenntt
ccoonntteenntt
Nitrogen UUrreeaa
AAmmmmoonniiuumm NNiittrraattee
AAmmmmoonniiuumm SSuullpphhaattee
Calcium Nitrate
MMaaggnneessiiuumm NNiittrraattee
UUrreeaa AAmmmmoonniiuumm NNiittrraattee
PPoottaassssiiuumm NNiittrraattee
Monoammonium Phosphate
4466--00--00
3344--00--00
2211--00--00
1166--00--00
1111--00--00
3322--00--00
1133--00--4466
3322--00--00
PPhhoosspphhoorruuss MMoonnooaammmmoonniiuumm PPhhoosspphhaattee
MMoonnooppoottaassssiiuumm PPhhoosspphhaattee
PPhhoosspphhoorriicc AAcciidd
1122--6611--00
00--5544--3322
00--8822--00
PPoottaassssiiuumm PPoottaassssiiuumm CChhlloorriiddee
Potassium Sulphate
PPoottaassssiiuumm NNiittrraattee
PPoottaassssiiuumm TThhiioossuullpphhaattee
Monopotassium Phosphate
00--00--6600
00--00--5500
1133--00--4466
00--00--2255
00--5522--3344
NNPPKK PPoollyyffeeeedd 1199--1199--1199
2200--2200--2200
MMiiccrroonnuuttrriieennttss FFee EEDDTTAA
FFee DDTTPPAA
FFee EEDDDDHHAA
ZZnn EEDDTTAA
CCaa EEDDTTAA
RReexxoolliinn CCXXKK ((BB++CCuu++FFee++MMnn++MMoo++ZZnn++MMgg))
1133
1122
66
1155
99..77
------
• Free from chlorides and sodium
• No salt build up in the crop root zone
• Contain 100% plant nutrients
• Fast acting nitrate nitrogen, soluble phosphorus and soluble postassium

68. 67
• Completely water soluble with any residues
• Most of the fertilizers are acidic in nature, hence no special chemical treatment
is required to check emitter plugging
• Maintain optimum soil pH contributing to more uptake of nutrients
• Most of the fertilizers are blended with micronutrients
Effect on Quality? Not Only Total Tonnage of Millable Stalks are to be
Considered, the Effect of the Fertilizer on Sugar Yield Has Also to be Taken into
Account:
It is well known that "sugar is made in the field, not in the factory". Sugar formation and
accumulation is a function of several variables viz., variety and age or duration of the
crop cycle, climatic conditions, soil fertility and fertilization. The effect of fertilization of
course reflects to a large extent the role played by the nutrient in the physiological
process within the plant, particularly photosynthesis, transport and accumulation of
sucrose (the sink source relationship).

Increase in the rate of N raises yields of stalk and sugar until yield reaches a
maximum. If N is applied in excess of the optimum, sugar production may drop. Timing
of N application has a profound influence on sucrose content at harvest. N application
at beginning of vegetative growth has no negative effect on sucrose content. However,
late application at 10 months caused a decrease in sugar yield of 14 g per stalk when
compared to the application before 7 months.

Higher rates of P (100 kg P2O5/ha) application can reduce yield, sugar concentration,
pol % and purity, particularly in ratoons and in soils not deficient in phosphorus. On the
other hand, in P deficient soils higher p levels increase pol % and purity. The amount
of P in cane juice has an effect on clarification and should be in the range of 132 to
264 ppm P when lime is used for clarification. Other methods of clarification may need
lower values.

Potassium application raises millable stalk yield, sugar % of cane and in brix % juice
also. K deficiency impairs sucrose transport from the leaf into the stalk (Fig.). There is
a positive interaction between N and K - the reduction in sugar content caused by high
rates of N is ameliorated by an adequate supply of K. Excessive dosages of K i.e.,
over and above optimal rates may exert a negative effect on apparent sucrose percent
in cane (pol % cane) and may promote an increase in the ash content of juice.
Increased ash content in cane juice has a negative influence on sugar quality since K
is the main constituent of juice ashes.

When k exceeds 1000 ppm in juice it is undesirable and affects manufacturing
process. Potassium passes through the clarification process affecting the exhaustion
of the final syrup, keeping a certain amount of sucrose in solution. K is a mellassigenic
substance because one mol of K holds one molecule of sucrose. The unfavourable

69. 68
effects of K however, should be anticipated only when excessive rates are used; in low
potassium soils improvement in cane quality are to be expected, as shown in Fig.


Effect of K Supply on Sucrose Yield, Sucrose and Fibre Content
(Malavolta, 1994)

Considering the above factors a model fertigation progremme is given in Table 18 for
12 months crop and Table 19 for 14-16 months crops. This is only a guideline, based
on the local soil, variety, climatic and management factors necessary adjustments can
be made to the programme.

Table 18. Fertigation Schedule for Seasonal (12 months)/Ratoon Sugarcane
NNuuttrriieennttss ((kkgg//hhaa//ddaayy)) DDaayyss AAfftteerr PPllaannttiinngg
NN PP22OO55 KK22OO
11--3300 DDaayyss 11..2200 00..1100 00..2200
3311--8800 DDaayyss 11..5500 00..4400 00..2244
8811--111100 DDaayyss 22..0000 11..0000 00..4400
111111--115500 DDaayyss 00..7755 00..3300 00..7755
115511--119900 DDaayyss ---- 11..5500

Table 19. Fertigation Schedule for Preseasonal (14 to 16 months) Sugarcane
NNuuttrriieennttss ((kkgg//hhaa//ddaayy))
DDaayyss AAfftteerr PPllaannttiinngg
NN PP22OO55 KK22OO
11--3300 DDaayyss 11..55 00..1155 00..2255
3311--8800 DDaayyss 22..00 00..6600 00..3300
8811--111100 DDaayyss 22..55 11..5500 00..5500
111111--115500 DDaayyss 00..7755 00..5500 11..00
115511--119900 DDaayyss ---- 11..8800

70. 69

Earthing Up

Earthing-up operation is also known as
"hilling-up". This operation is carried out in
two or three stages.The first earthing-up
operation is known partial earthing-up and
the second/third operation is known as "full
earthing-up".

The partial earthing-up is done at 45 days
after planting. In partial earthing-up, little
amount of soil from either side of the
furrow is taken and placed around the base
of the shoots. While doing partial earthing-
up, the furrow in which the cane row is
present gets partially filled-up.

Full earthing-up is done after 120 days
after planting coinciding with the peak tiller
population stage. During full earthing-up
the soil from the ridge in between is fully
removed and placed near the cane on either side. This operation converts the furrows
into ridges and ridges into furrows.This operation could be done either manually or by
using a bullock-drawn/tractor drawn furrower depending upon the spacing adopted. (In
the picture: Earthing up or hilling up by machinery)

Full earthing-up at the end of formative phase (i.e., 120 DAP) checks further tillering,
provides sufficient soil volume for root proliferation, promotes better soil aeration and
provides a sound anchorage or support to the crop and thus preventing lodging.

One more earthing-up after cane population is stabilized at 180 DAP may be helpful in
preventing lodging and water shoots formation. It also improves aeration and helps to
control weeds.

Detrashing

Detrashing refers to removal of unwanted bottom dry and green leaves at regular
intervals. Sugarcane stalk bears large number of leaves (30-35) equal to the number of
inter-nodes under good management systems.

However, all these leaves are not productive, only top eight to ten leaves are required
for optimum photosynthesis. In fact the bottom green leaves are parasitic on the upper
productive leaves and drain out the food reserves (photosynthates) which other wise

71. 70
could be used for stalk growth. Therefore, in sugarcane it is important to remove the
lower dry and green leaves.


In the picture: Detrashing in sugarcane is beneficial in many ways

Detrashing should be taken up after the cane formation around 150 days after planting. There after it could be done at bi-monthly interval depending up on the labour availability.

Detrashing helps in:

Maintaining clean field
• Enhances air movement and enriches Co² with in the crop canopy providing an
ideal micro-climate for unrestricted growth of cane
• More food material is made available for stalk growth
• Reduces the problem of infestation of several insect-pests like scales, mealy
bug, white flies etc
• Reduces bud sprouting due to accumulation of water inside the sheath in some
varieties.
• Bud sprouting is not desirable as it would reduce main stalk growth and affect
sugar accumulation
• Facilitates easy entry and movement in the field, particularly to inspect the
condition of the crop and drip laterals and thus accordingly plan the fertigation
and plant protection schedules
• A clean field minimizes rodents, rats, squirrels in the field which may otherwise
cause damage to the crop
• Facilitates easy and economy in harvesting besides clean canes for crushing
• Detrashed trash can be used as a mulch for moisture conservation

72. 71
• Clean leaves can be used for composting

Propping

The operation of tying the leaves together using the bottom dry and green leaves is
known as propping. It is primarily done to check lodging of cane. Usually the trash
without removing from the cane is twisted to form a sort of rope and cane stalks are
tied together. This is known as trash-twist propping. Propping can be either done for
each row or two rows can be brought together and tied.

In India bamboo poles are used and propping is done in certain pockets, but it is too
expensive. In areas where cane top growth is heavy and wind velocities are high,
propping is very much necessary to prevent lodging. This is because lodging leads to
several problems:
• Cane breakage and thus loss of stalk number at harvest and thus loss of cane
yield
• Infestation of certain pests and diseases causing microbes through lodged and
damaged canes
• Damage by rats and rodents
• Bud sprouting leading to reduced cane quality
• Aerial root formation which also affects cane quality
• Difficulty in inspection of driplines and harvesting


In the Picture: Propping in sugarcane prevents lodging and minimizes pests

73. 72
Removal of Water Shoots

Water shoots are the late-formed tillers or side shoots, which are robust and fast
growing. They originate mainly due to plentiful supply of water, inadequate earthing-up
and late fertigation. These water shoots, as the name indicates, contain lot of water
and less sucrose and more of reducing sugars.

Water shoots affects the growth of adjacent stalks. They harbour insect-pests and
when they are harvested and sent to mill for crushing, lead to reduced juice quality and
affect sugar recoveries. Therefore it is advisable to remove water shoots as and when
they arise. The water shoots can be used as cattle feed.

Harvesting Management

Harvesting of sugarcane at a proper time i.e., peak maturity, by adopting right
technique is necessary to realize maximum weight of the millable canes (thus sugar)
produced with least possible field losses under the given growing environment.

On the other hand harvesting either under-aged or over-aged cane with improper
method of harvesting leads to loss in cane yield, sugar recovery, poor juice quality and
problems in milling due to extraneous matter.

Therefore, proper harvesting should ensure:

• To harvest the cane at peak maturity (i.e., avoiding cutting of either over-
matured or under-matured cane)
• Cutting cane to ground level so that the bottom sugar rich internodes are
harvested which add to yield and sugar
• De-topping at appropriate height so that the top immature internodes are
eliminated
• Proper cleaning of the cane i.e., removing the extraneous matter such as
leaves, trash, roots etc.
• Quick disposal of the harvested cane to factory
Several standard analytical methods are available to determine the peak maturity or
quality so that the cane is harvested at right time. Without such analysis also several
farmers take-up cane harvesting based on crop age and appearance. Sometimes
farmers harvest the crop even before the crop fully matures due to necessity to supply
cane to the mills early.

Likewise delays in harvesting are also quite common, particularly when there is excess
cane area. To avoid such extremes harvesting should be done at right time employing

74. 73
right method. The following criteria enable harvesting of cane at right time adopting
proper procedures:

Crop Age
Harvesting is done based on maturity (age) group. Farmers who grow a particular
variety are usually conversant with the harvesting time. Even most sugar factories give
cutting orders to farmers based on crop age. This is not a scientific method since,
planting time, crop management practices, weather conditions etc influences maturity.

Visual Symptoms
Yellowing and drying of leaves, metallic sound of mature canes when tapped,
appearance of sugar crystal glistening when a mature cane is cut in a slanting way and
held against the sun are some of the visual indices of assessing maturity of cane.

Quality Parameters
Important sugarcane quality parameters for assessing cane maturity are the juice Brix,
pol or sucrose percentage and purity.
• Juice Brix: Juice Brix refers to the total solids content present in the juice
expressed in percentage. Brix includes sugars as well as non-sugars. Brix can
be measured in the field itself in the standing cane crop using a Hand
Refractometer. This is usually referred as a Hand Refractometer Brix or HR
Brix. In the field using a pierce collect composite juice samples from several
canes. Then place a drop of the composite juice sample in the Hand
Refractometer and measure the Brix reading.
The circular field gets darkened relative to the Brix level, which could be easily
read. The HR Brix meter has graduations from 0 to 32 per cent. The HR Brix
readings can be separately taken from both top and bottom. A narrow range
indicates ripeness of the cane, while a wide difference indicates that the cane is
yet too ripe. On the other-hand if the bottom portion of the cane has lower Brix
value than the top, it means that the cane is over-ripened and reversion of sugar
is taking place.
• Juice Sucrose Or Pol Per Cent: The juice sucrose per cent is the actual cane
sugar present in the juice. It is determined by using a polarimeter, hence
sucrose per cent is also referred to as pol per cent. For all practical purposes
pol % and sucrose % are synonyms. Now a days an instrument called
sucrolyser is also available for determining sucrose % in juice.
• Purity Coefficient: It refers to the percentage of sucrose present in the total
solids content in the juice. A higher purity indicates the presence of higher
sucrose content out of the total solids present in juice. The purity percentage
along with sucrose percent aids in determining maturity time.

75. 74
Purity Percentage = (Sucrose %/HR Brix)100
A cane crop is considered fit for harvesting if it has attained a minimum of
16% sucrose and 85% purity.
• Reducing Sugars: The reducing sugars refer to the percentage of other
sugars (fructose and glucose) in the juice. A lower reducing sugars value
indicates that much of the sugars have been converted into sucrose.
• Commercial Cane Sugar: The commercial cane sugar (CCS) refers to the total
recoverable sugar percent in the cane. This could be calculated by the following
formula:
CCS (tons/ha) = [Yield (tons/ha) x Sugar Recovery (%)] /100
Sugar Recovery (%) = [S - 0.4 (B - S)] x 0.73
Where, S= Sucrose % in juice and B= Corrected Brix (%)

Manual Harvesting

In many countries even today harvesting is done
manually using various types of hand knives or hand
axes.Among the several tools the cutting blade is
usually heavier and facilitates easier and efficient
cutting of cane.

Manual harvesting requires skilled labourers as
improper harvest of cane leads to loss of cane & sugar
yield, poor juice quality and problems in milling due to
extraneous matter.

(In the picture: Manual harvesting of sugarcane)



Mechanical Harvesting
Harvesting labour is becoming scarce and
costly in view of diversion of labour to other
remunerative work in industry, construction,
business etc. Mill stoppages because of non-
availability of canes are not uncommon owing
to shortage of harvesting labour. And, most of
the new mills are of higher crushing capacity
and many are expanding their crushing
capacities. Therefore daily requirement of
cane is increasing and hence greater
demand for harvesting labour.

76. 75

Added to this most of the present day agricultural labourers are not interested in field
operations involving much drudgery. Thus in years to come, the labour position is likely
to deteriorate further. Therefore mechanization is inevitable and hence, adoption of
mechanical harvesting of cane in future is inevitable. (In the picture:
Mechanical harvesting of sugarcane)

In countries like Australia, Brazil, USA, South Africa, Taiwan, Thailand etc where
sugarcane cultivation is highly mechanized huge harvesters are employed for cane
harvesting. In these countries, sugarcane is grown on large plantation scale in large
farms owned by either mills or big farmers. The field capacity of mechanical cane
harvesters varies with the size (2.5 to 4 ha per day of 8 hours.

The limitation of mechanical harvesters is use of such machines in small, irregular and
fragmented holdings, diversified cropping patterns, limited resource capacity of small &
marginal farmers in several countries.

Yield

Sugar yield depends on cane tonnage, sugar content of the cane and on the cane
quality. It is important that the cane is harvested at the most suitable time when the
economic optimum of recoverable sugar per area is reached.

Cane tonnage at harvest with best management practices under drip ferti-irrigation can
vary between 150 and 175 ton/ha in sub-tropical zone and between 150 to 300
tons/ha, which depends particularly on the length of the total growing period and
whether it is a plant or a ratoon crop. The water utilization efficiency for harvested cane
yield containing about 80 percent moisture is around 15 to 20 kg/m
3


Toward maturity, vegetative growth is reduced and sugar content of the cane
increases greatly. Sugar content at harvest is usually between 10 and 12 percent of
the cane fresh weight, but under experimental conditions 18 percent or more has been
observed. Sugar content seems to decrease slightly with increased cane yields.

Luxurious growth should be avoided during cane ripening, which can be achieved by
low temperature, low nitrogen level and restricted water supply. With respect to juice
purity, low minimum temperatures positively affect this several weeks before harvest.

Nutrient Deficiency Symptoms

Nitrogen
• Die back of older leaves.
• Leaf baldes turn light green to yellow.

77. 76

In the picture: Nitrogen deficiency symptom (Source: D.L. Anderson)
• Short and slender stalks
• Tips and margins of older leaves become necrotic.
Phosphorus


In the picture: phosphorus deficiency symptom

78. 77
• Red and purple discolouration of tips and margins
• Slender leaves
• Short sand slender stalks
• Poor or no tillering
Potassium
• Yellow-orange chlorosis of leaf borders & tips
• Stalks slender
• Older leaves brown or "fired"
• Spindles distorted producing "bunched top" or "fan' appearance.
Calcium
• Mottling and chlorosis of older leaves
• Spindles often become necrotic at the leaf tip and long margins
• Rusty appearance and premature death of older leaves
Magnesium
• Mottled or chlorotic appearance at the tip and margins
• Red necrotic lesions resulting in "rusty" appearance
• Internal browning of rind

In the picture (Source: D.L. Anderson):
Magnesium deficiency symptom

79. 78
Sulphur
• Chlorotic young leaves
• Narrower and shorter leaves with faint purplish tinge
• Slender stalks
Copper
• Green splotches with leaves eventually showing bleaching
• Stalk and meristems lack turgidity
• Reduced internodal length and tillering.
Iron
• Varying degrees of chlorosis
• Interveinal chlorosis from tip to base of leaves.


In the picture :
Iron deficiency symptom

80. 79
Manganese
• Occurrence of interveinal chlorosis from leaf tip towards the middle of leaf.
• Bleaching of leaves under severe deficiency.
Boron
• Distorted leaves
• Formation of translucent lesions or water sacks along leaf margins
• Brittle and bunched with many tillers
• Death of apical meristem.
Molybdenum
• Short longitudinal chlorotic streaks on the top one-third of the leaf.
• Short and slender stalks
• Slow vegetative growth.


In the picture: Molybdenum deficiency symptom (source: J.E. Bowen)

Zinc
• Midrib and leaf margin remain green and yellowing of leaf blade
• Red lesions on leaves
• Reduced tillering and shorter internodes
• Thin stalks with loss of turgidity.

81. 80
Pests and Diseases

Matching with long diversity of conditions under which sugarcane is grown in the world,
there is wide spectrum of pests and diseases which have come to acquire a place of
priority for control on regional or inter-regional basis due to the agro-climatic
management conditions associated with the area.

In addition the susceptibility of the variety to the diseases and pests aggravates the
situation and creates additive problems. Below herein is given a brief account of
symptoms of important pests and diseases occurring in several parts of the world. For
more information and pest and disease control measures consult the local Netafim
Agronomist or Plant protection expert.

Early Shoot Borer (Chilo infescatellus)- Symptoms

• Attacks the crop during the early part of cane growth, before internode
formation. It also attacks the cane stalks in the years of scanty rainfall
• Larvae enter the cane laterally through one or more holes in the stalks (shoot)
and bores downwards as well as upwards killing the growing point. Thus it cuts
of the central leaf spindle, which eventually dries forming a ‘dead heart'. The
dead heart can be easily pulled out. It emits an offensive odour.
• Borer infestation during the germination phase kills the mother shoots resulting
in the drying up of the entire clump. This leads to gaps in the field.
• Causes heavy yield losses as it affects the plant stand/unit area. It also leads to
canes of different age, which will be poor in juice quality, with less cane weight.
When borer infects cane stalks, both yield and quality are reduced.

Internode Borer (Chilo Saccharifagus Indicus) - Symptoms

• Damages the crop soon after internode
formation and its activity continues till hatvest
• Lodging, high dosage of nitrogen, waterlogged
condition and presence of water shoots favour
buildup of pest
• Fresh borer attack is mostly found in the top five
immature internodes
• Caterpillars bore at the nodal region and enter
the stem and tunnel up-wards in a characteristic
spiral fashion. Entrance hole is usually plugged
with excreta.

82. 81
• Larvae feed and multiply in water shoots. One larvae found in a single cane
damages 1-3 internodes. The length and girth of the infected internodes get
reduced.
• Yield loss and juice quality deterioration occurs when the infestation is severe
(In the picture above: Internode borer damage)
Top Borer (Scirpophaga Excerptalis)
• Waterlogging favours moth attack
• Larva first tunnels into the midrib of the leaves and causes a white streak which
later turns reddish brown usually in the second to fifth leaf from the top. As a
result of biting across the spindle, a number of shot holes are formed in the leaf.
As larva nibbles into the central core of the cane a portion of the internal tissue
is eaten resulting in dead heart formation. Dead heart when formed is reddish
brown, appears charred, and cannot be easily pulled out. In tillering phase of
the crop, the attacked shoots die, side shoots (tillers) develop producing a
bunchy top appearance. In the grand growth period, the crop growth is arrested,
and the crown with dead heart dries and may be blown off leaving the stump.
• Severe yield loss and quality deterioration occurs due to top borer. Depending
upon the incidence level yield loss may be up to 20-30%.
Scale Insect (Melanaspis Glomerata)
• Waterlogging, high temperature and humidity favour buildup of scale insect
population. Rainwater and high wind velocity facilitate dispersal of the pest. It
spreads to new areas through seed material. Men and animals passing through
the infested fields also lead to spread of the pest to the adjoining areas.
• Scales usually establish on internodes covered with leaf sheath. The leaves of
infested canes show signs of tip drying and unhealthy pale green colour and
with continued infestation turn yellow. Desapping leads to non-opening of
leaves also, which also turn yellow and finally dry out. Nodal region is more
infested than internodal region.
• Infested crop losses its vigour, canes shrivel, growth is stunted and the
internodal length is reduced drastically. Ultimately cane dries up. Such canes
when slit open appear brownish red. Thus yield and quality suffer. The yield loss
could range from negligible to total crop failure.
Pyrilla (Pyrilla purpusilla Walker)
• Pyrilla is the most destructive foliage-sucking pest of sugarcane
• Heavy rainfall followed by 75-80% humidity, intermittent drought periods, high
temperature (26-30°c) and wind movement favour rapid buildup of pyrilla. Other
factors favouring pyrilla buildup are dense and luxuriant crop, excess nitrogen

83. 82
application, water logging, lodging of cane and varieties with broad and
succulent leaves.
• Adults and the nymps suck leaf sap from the under surface of the lower leaves.
When the infestation is heavy, leaves turn yellowish white and wither away. Due
to continuous desapping by large number of hoppers top leaves in the affected
canes dry up and lateral buds germinate. The hoppers exude a sweet sticky
fluid known as honeydew, which promotes quick and luxuriant growth of the
fungus, capanodium species and as a result the leaves are completely covered
by the sooty mould. This affects photosynthesis.
• The loss in cane yield due to pyrilla have been estimated to be around 28% with
about 1.6% unit loss in sugar.
Termites (Coptotermes Heimi Wasmann; Odontotermes Assmuthi Holmgr; O.
Obesus Rambur; O. Wallonensis Wasmann; Microtermes Obesi Holmgr;
Trinervitermes Biformis Wasmann)
• Polyphagous and found throughout the world. More serious under prolonged
drought conditions and in light textured soils viz., sandy and sandy loam soils
• The termites attack setts, shoots, canes and also stubbles
• The termites gain entry through the cut ends or through buds of the setts and
feed on the soft tissue. The tunnel excavated is filled with the soil. This affects
germination and thus the initial crop stand and ultimately the cane yield. The
germination failure could be up to 60%.
• In the stalks the termites feed on the inner tissues leaving the rind intact. The
cavity formed is filled up with moist soil, having galleries, in which, they move
about. The affected canes die.
Whitefly (Aleurolobus Barodensis Mask)
• Waterlogging and nitrogen
starvation cause severe out break
of whiteflies. Summer droughts
and dry spells during monsoon
season also favour buildup of this
pest
• Varieties with broad and long
leaves are more susceptible to
this pest
• The nymphs of white flies suck
the sap from the under surface of
leaves which turn yellow and
pinkish in severe cases and
gradually dry up.
• Heavy infested leaves are

84. 83
covered by the sooty mould caused by the fungus, which adversely affects
photosynthesis. The whitefly infestation retards cane growth and reduces sugar
content
• Considerable loss on yield and sugar recovery has been observed. At 80% leaf
infestation 23.4% loss in cane yield and 2.9% units loss in sucrose has been
reported. (In the picture above: White fly infestation)
Red Rot (Colletotrichum Falcatum)
• It is the most dreaded disease of sugarcane which has caused the elimination of
several important sugarcane varieties from cultivation
• Yellowing and drying of leaves from margin to midrib, drying of the entire top
including the crown, loss of natural colour and considerable shrinkage of the
stalk, appearance of reddish lesions on the rind are some of the external
symptoms of red rot disease.
• Most characteristic and diagnostic symptom of the disease is the presence of
reddish discoloured patches or lesions interspersed with white horizontal
patches on the internal tissue. As the diseases progresses the internal tissues
become dark in colour and dry resulting in longitudinal pith cavities.
Smut (Ustilago Scitaminea)
• Primary spread of the disease is through infected setts and the secondary
spread is through wind borne teliospore
• Stunting of infected stools, profuse sprouting of lateral shoots i.e., tillers,
reduction in internodal length, formation of thin stalks and narrow erect leaves
are certain symptoms of smut.
• Characteristic symptom is the production of long whip like structure from the
terminal bud of the stalk, which is black in colour covered by thin silvery
membrane. This silvery membrane ruptures releasing millions of reproductive
spores of smut fungus, which are present in the form of powdery mass.
• Losses due to smut in sugarcane depend on various factors viz., primary or
secondary infection, plant or ratoon crop that is affected and early or late
infection and have been reported to range from 30 - 40% in plant crops and
even up to 70% in ratoons. Sucrose content of infected cane is reduced to 3 -
7%.
Pineapple Disease (Ceratocystis Paradoxa)
• Essentially a disease of seed material i.e., setts. Typical disease symptoms are
detected in setts after 2 - 3 weeks of planting.
• Pathogen enters the sett mainly through the cut ends and destroy the central
soft portion i.e., parachymatous tissues of the internode and then damages the
buds.

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• Affected tissues first develop a reddish colour, which turns to brownish black in
the later stages. Cavities are formed inside the severely affected internodes.
The presence of the fungus inside the sett prevents their rooting. In most cases
setts decay before bud sprouts or the shoots grown to an height of 6 - 12cm.
Thus causing germination failure leading to reduced initial crop stand per unit
area.
• Occasionally, the disease occurs in standing crop too due to the entry of the
pathogen through stalk damaged by borers, rat damage or any such injuries.
Drought accelerates the damage. Pathogen spreads rapidly throughout the
canes, foliage turns yellow, and ultimately plant withers. The diseased stalk
when cut open smells like mature pineapple. The pineapple odour is due to
production of ethyl acetate by the fungus.
Wilt (Cephalosporium Sacchari)
• Disease spreads through infected setts. The fungi gain entry mainly through
injuries.
• Biotic stresses like nematode, root borer, termite, scales, mealy bugs etc and
abiotic stresses like drought, water logging etc predispose the plants for wilt
infection
• Moisture stress coupled with high temperature and low humidity reduces plant
resistance to wilt.
• Typical wilt symptoms appear during monsoon and post monsoon periods.
• Affected plant appears wilted and conspicuously stunted. The crown leaves turn
yellow, loose turgor and eventually withers.
• Wilt-affected canes loose their normal colour and are light in weight. The most
characteristic symptom during the early stage of infection is the presence of
diffused reddish brown patches on the internal tissue. Later canes become light
and hallow and shrink.
• Disease reduces germination and in severe cases total cane yield losses occur
due to drying up of shoots and wilting of the stalks.


Ratoon Stunting Disease

• Ratoon stunting disease has been considered as the most important cause for
sugarcane varietal degeneration
• Primary spread of the disease is through infected setts.
• Also spreads through harvesting implements contaminated with the juice of
diseased canes.
• Expression of disease is more under adverse conditions.

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• Progressive yield decline takes place due to the disease. Ratoon crop suffers
more damage due to RSD than the plant
crop.
• Disease is known to reduce germination
and yield
• Most characteristic symptom of the infected
stalks is the presence of pin head like
orange coloured dots of bacteria on the
internal soft tissue in the nodal region.
• Other symptoms include stunted growth,
thin stalks with short internodes, pale
yellowish foliage and rapid tapering of the
stem towards the top


(In the picture above: Ratoon stunting disease
symptom)

Grassy Shoot Disease (Phytoplasma)
• It is a mycoplasamal disease.
• Primary transmission of disease is through disease infected setts
• Profuse tillering with narrow chlorotic leaves giving a grass like appearance is
characteristic symptom of GSD incidence
• Very few tillers of GSD infected plants develop into canes, which are thin and
produce white shoots from the side buds.
Leaf Scald (Xanthomonas Albileneans)
• It is a bacterial disease, widely spread in many countries.
• Disease is favoured by wet seasons, water stress due to drought, water logging
and low temperatures.
• Disease symptoms appear in two phases, the chronic and acute phases.
• In the chronic phase, "white pencil line" extending entire length of lamina
reaching the margin of young leaves and stripes diffuse later resulting in leaf
etiolation. Drying from tip onwards presents a scalded appearance and hence
the name. Different degrees of chlorosis from total albinism to interveinal
chlorosis in young leaves during summer, germination of buds in acropetal
manner with bushy appearance in standing cane, cut open stalks showing dark
red vascular strands, prominent streaks at node invariably in the side shoots,
are other prominent symptoms of chronic phase.

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• In the acute phase the symptoms appear suddenly and die without any major
leaf symptoms. The masking of symptoms is more common during monsoon
and symptoms may appear suddenly any time during crop growth.

Yellow Leaf Spoot (Cercospora Koepkei)

• Prolonged rain with intermittent sunshine,
waterlogged conditions and higher nitrogen
doses are congenial for disease development.
• Warm humid weather favours rapid and
abundant production of conidia by the
pathogen and sopread of the disease.
• Characteristic symptoms are presence of
small, yellow coloured, irregularly shaped
spots over the leaf surface. Density of spots is
minimum in the lower surface, moderate in the
middle and maximum towards the tip of the
leaf. Spots coalesce at late stages and cause
drying of leaves. Badly affected foliage looks
reddish-brown when viewed from a distance.
In the picture: Yellow leaf spot showing small yellow coloured spots

Eye spot (Helminthosporium sacchari)
• Usually a crop of 6 - 7 months is more susceptible to the disease.
• Fungus penetrates the host tissue either through stomota, bulliform cells or
directly through the cuticle.
• Cloudy weather, high humidity with drizzle coupled with low night temperatures,
wetting of leaves either through precipitation or dew greatly enhance disease
development.
• Likewise water logging, high fertility status and excess nitrogen fertilization also
favour the spread of the disease.
• Lesions first appear as small water soaked spots, darker than the surrounding
tissues. The spot becomes more elongated, resembling the shape of an ‘eye'
and turns straw coloured within a few days. Finally the central portion becomes
reddish brown surrounded by straw coloured tissues. Then reddish brown
streaks of ‘runners' develop extending from the lesions towards the leaf tip
along the veins. Later the spots and streaks coalesce to form large patches and
causes drying of leaves.
- The End -